Lens barrel

ABSTRACT

A lens barrel includes at least one lens, the optical axis of the lens; the first frame (the fixed frame 900) having the first restricting portion (901, 902) and having an approximately cylindrical shape about the optical axis; the second frame (1000) having the cam groove (1036) and having an approximately cylindrical shape about the optical axis; the third frame (510) having the guide portion (511) which restricts inclination thereof with respect to the first contact portion (514) and the optical axis and having an approximately cylindrical shape about the optical axis; the drive arm (520) having a cam follower (523), the second restricting portion (524, 525) and the second contact portion (526), and having an approximately arcuate shape constituted of a portion of a circular cylinder about the optical axis or an approximately plate shape; the guide shaft (601) for guiding the guide in a movable manner in the optical axis direction; and the spring (603). The first restricting portion engages with the second restricting portion. The cam engages with the cam groove (1036). The drive arm moves approximately parallel to the optical axis due to the relative rotation of the second with respect to the first frame, the third is biased by the thus bringing the first contact portion and the second contact portion into contact with each other, and the third frame moves in the optical axis direction in an interlocking manner with the drive with the inclination of the guide being restricted by the guide.

BACKGROUND

1. Technical Field

The present disclosure relates to a lens barrel provided with an opticalsystem.

2. Related Art

JP 2012-53411 A discloses a lens barrel which enables zooming.

SUMMARY

It is an object of the present disclosure to miniaturize (to decrease athickness of) a lens barrel in the optical axis direction.

A lens barrel according to a first aspect of the present disclosureincludes

at least one lens,

an optical axis of the lens,

a first frame including a first restricting portion, the first framehaving an approximately cylindrical shape about the optical axis,

a second frame including a cam groove, the second frame having anapproximately cylindrical shape about the optical axis,

a third frame including a first contact portion and a guide portionwhich restricts the inclination of the third frame with respect to theoptical axis, the third frame having an approximately cylindrical shapeabout the optical axis,

a drive arm including a cam follower, a second restricting portion and asecond contact portion, the drive arm having an approximately arc shapeconstituted of a portion of a circular cylinder about the optical axisor an approximately plate shape,

a guide shaft for guiding the guide portion in a movable manner in anoptical axis direction, and

a spring, wherein

the first restricting portion engages with the second restrictingportion,

the cam follower engages with the cam groove, and

along with the rotation of the second frame relative to the first frame,the drive arm moves approximately parallel to the optical axis, thethird frame is biased by the spring so that the first contact portionand the second contact portion are brought into contact with each other,and

the third frame moves in the optical axis direction in an interlockingmanner with the drive arm in a state where the inclination of the guideportion is restricted by the guide shaft.

According to the lens barrel of the present disclosure, a lens barrelcan be miniaturized (can be made thin) in the optical axis direction.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a digital camera 3000;

FIG. 2A is a perspective view showing a collapsed state of a lens barrel2000;

FIG. 2B is a perspective view showing a telescopic state of the lensbarrel 2000;

FIG. 3 is an exploded perspective view of the lens barrel 2000;

FIG. 4 is an exploded perspective view of a third group unit 300;

FIGS. 5A and 5B are constitutional views of an OIS actuator;

FIGS. 6A and 6B are explanatory views of a magnetic attraction force ofthe OIS actuator;

FIGS. 7A and 7B are explanatory views showing power consumption of theOIS actuator;

FIGS. 8A and 8B are views showing an assembling method of the thirdgroup unit 300;

FIG. 9 is a perspective view showing the relationship between the thirdgroup unit 300 and a rotation restricting frame 1200;

FIGS. 10A and 10B are a side view and a cross-sectional view showing therelationship between the third group unit 300 and the rotationrestricting frame 1200;

FIGS. 11A and 11B are views showing a retracting operation of aretracting lens frame 310;

FIGS. 12A to 12C are a front view and cross-sectional views showing therelationship between the third group unit 300 and the rotationrestricting frame 1200;

FIG. 13A is an exploded perspective view of a drive frame unit 1000;

FIG. 13B is a view showing a second drive frame 1030;

FIG. 14 is a perspective view of a penetration cam frame 1100;

FIGS. 15A(a) and 15A(b) are views for describing the relationshipbetween the drive frame unit 1000 and the penetration cam frame 1100;

FIGS. 15B(a) and 15B(b) are view for describing the relationship betweenthe drive frame unit 1000 and the penetration cam frame 1100;

FIG. 16 is a perspective view of a double-sided cam frame 1310;

FIGS. 17A to 17C are a front view and views as viewed in the directionindicated by arrows of the double-sided cam frame 1310;

FIG. 18 is a developed view of the penetration cam frame 1100;

FIGS. 19A and 19B are views showing the relationship (a collapsed state)between the drive frame unit 1000, the penetration cam frame 1100 andthe double-sided cam frame 1310;

FIGS. 20A and 20B are views showing the relationship (a telescopicstate) between the drive frame unit 1000, the penetration cam frame 1100and the double-sided cam frame 1310;

FIG. 21 is an exploded perspective view for describing driving of afifth group unit 500;

FIG. 22 is a view for describing the relationship between thepenetration cam frame 1100 and a fifth group drive arm 520;

FIG. 23 is a view for describing the relationship between a fixed frame900, the penetration cam frame 1100, and the fifth group drive arm 520;

FIG. 24 is a view for describing the relationship between a second driveframe 1030 and the fifth group drive arm 520;

FIG. 25 is a cross-sectional view of the lens barrel 2000 in a collapsedstate;

FIG. 26 is a cross-sectional view of the lens barrel 2000 in atelescopic state;

FIG. 27 is a cross-sectional view of the lens barrel 2000 in atelescopic state;

FIG. 28 is a perspective view showing the relationship between thedouble-sided cam frame 1310 and an ornamental frame 1320;

FIG. 29 is an exploded perspective view of the double-sided cam frame1310 and the ornamental frame 1320; and

FIGS. 30A and 30B are constitutional views showing another example ofthe OIS actuator.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Hereinafter, an embodiment is described in detail with reference todrawings. However, the detailed explanation of the embodiment more thannecessary may be omitted. For example, the detailed description ofmatters which are already well-known or the repeated explanation of thesubstantially identical constitutions may be omitted. Such omission canprevent the explanation made hereinafter from becoming unduly redundantthus facilitating the understanding of the present disclosure by thosewho are skilled in the art.

Inventors of the present invention provide attached drawings and theexplanation made hereinafter for enabling those who are skilled in theart to sufficiently understand the present disclosure, and the inventorsdo not intend to limit the invention called for in Claims by thedrawings and the explanation.

The embodiment of the present disclosure is described with reference todrawings. In the description made hereinafter with reference todrawings, identical or similar portions are given the same or similarsymbols. However, the drawings are schematic views and hence, there maybe a case where a size ratio between respective parts and the likediffer from those of an actual product. Accordingly, specific sizes andthe like should be determined by taking into account the explanationmade hereinafter. It is also needless to say that portions are describeddifferently from each other with respect to a size relationship and asize ratio among drawings.

In the following embodiment, the explanation is made by taking a digitalcamera as an example of an imaging device. In the explanation madehereinafter, using a digital camera in a horizontal position as thereference, a subject side is expressed as “front”, a side opposite tothe subject is expressed as “rear”, a vertically upper side is expressedas “up”, a vertically lower side is expressed as “down”, a right sidewhen a user views a lens barrel from the subject side is expressed as“right”, and a left side when the user views the lens barrel from thesubject side is expressed as “left”. The horizontal position is a kindof posture of the digital camera. When a user takes a picture in ahorizontal position, a long-side direction of a horizontally-elongatedrectangular image substantially agrees with the horizontal direction inan image. A vertical position is another kind of posture of the digitalcamera. When the user takes a picture in the vertical position, thelong-side direction of a horizontally-elongated rectangular imagesubstantially agrees with the vertical direction in the image. Withrespect to a lens barrel of a camera, there may be a case where a centerside in the radial direction is referred to as “inner peripheral side”,and a side opposite to the center side in the radial direction isreferred to as “outer peripheral side”. There may be also a case wherethe direction toward a side opposite to the radial center in the radialdirection of the lens barrel of the camera is referred to as “outerperipheral direction”.

[1. Overall constitution of digital camera (FIG. 1, FIG. 2A, FIG. 2B)]

The constitution of a digital camera 3000 is described with reference todrawings. FIG. 1 is a perspective view of the digital camera 3000. FIG.2A and FIG. 2B are perspective views of a lens barrel 2000. The lensbarrel 2000 in a collapsed state is shown in FIG. 2A, while the lensbarrel 2000 in a telescopic state is shown in FIG. 2B. In thisembodiment, the telescopic state is a state where the lens barrel isextended the most.

As shown in FIG. 1, the digital camera 3000 includes a housing 3100, andthe lens barrel 2000.

The lens barrel 2000 is a three-stage collapsible lens barrel. The lensbarrel 2000 is housed in the housing 3100 when photographing is notperformed, and is extended frontwardly when photographing is performed.To be more specific, as shown in FIG. 2A and FIG. 2B, the lens barrel2000 includes: a first movable barrel portion 2100; a second movablebarrel portion 2200; a third movable barrel portion 2300; and a fixedbarrel portion 2400.

The first movable barrel portion 2100 is extendable with respect to thefixed barrel portion 2400. The second movable barrel portion 2200 isextendable with respect to the first movable barrel portion 2100. Thethird movable barrel portion 2300 is extendable with respect to thesecond movable barrel portion 2200. The fixed barrel portion 2400 isfixed to the inside of the housing 3100. As shown in FIG. 2B, when thelens barrel 2000 is extended, the third movable barrel portion 2300 ispositioned at the frontmost side out of the first to third movablebarrel portions 2100 to 2300.

[2. Constitution of Lens Barrel (FIG. 3)]

FIG. 3 is an exploded perspective view of the lens barrel 2000. Thischapter and FIG. 3 are provided for describing the schematicconstitution of the lens barrel, and there may be a case where symbolsin the chapter and symbols used in the sentences are omitted in thesedrawings.

The first to third movable barrel portions 2100 to 2300 of the lensbarrel 2000 are extended from the fixed barrel portion 2400 along anoptical axis AX of an optical system. The optical system includes afirst lens group L1 to a sixth lens group L6. In the explanation madehereinafter, the direction parallel to the optical axis AX is referredto as “optical axis direction”, the direction orthogonal to the opticalaxis direction is referred to as “radial direction”, and the directionalong a circle about the optical axis AX is referred to as“circumferential direction”. The optical axis AX substantially agreeswith axes of respective frames which constitute the lens barrel 2000.

As shown in FIG. 3, the lens barrel 2000 includes: a first group unit100; a second group unit 200; a third group unit 300; a fourth groupunit 400; a fifth group unit 500; a master flange unit 600; an imagingelement unit 700; a flexible printed circuit board 800; a fixed frame900; a drive frame unit 1000; a penetration cam frame 1100; a rotationrestricting frame 1200; a double-sided cam frame unit 1300; and ashutter unit 1400.

In this embodiment, the fixed frame 900 and the master flange unit 600constitute the fixed barrel portion 2400. The first group unit 100constitutes the third movable barrel portion 2300. The rotationrestricting frame 1200 and the double-sided cam frame unit 1300constitute the second movable barrel portion 2200. The drive frame unit1000 and the penetration cam frame 1100 constitute the first movablebarrel portion 2100.

The fixed frame 900 is formed in a circular cylindrical shape. Arotation restricting groove and a cam groove are formed on an innerperipheral surface of the fixed frame 900. A zooming motor unit 910 ismounted on an outer peripheral surface of the fixed frame 900. Thezooming motor unit 910 is a drive source for extending the first tothird movable barrel portions 2100 to 2300.

The master flange unit 600 is a plate-like member made of a resin whichcovers a rear portion of the fixed frame 900. The sixth lens group L6 isheld on a front side of the radial center of the master flange unit 600.The imaging element unit 700 is fitted in a rear side of the radialcenter of the master flange unit 600.

The drive frame unit 1000 is formed in a circular cylindrical shape. Thedrive frame unit 1000 is arranged on an inner peripheral side of thefixed frame 900. The drive frame unit 1000 includes: rotationrestricting grooves 1024, 1035; lifting cam grooves 1032; driving camgrooves 1036; cam followers 1038; and a driven gear portion 1037. Therotation restricting grooves 1024, 1035 are formed on an innerperipheral surface of the drive frame unit 1000 along the optical axisdirection. The lifting cam groove 1032 is formed on the inner peripheralsurface of the drive frame unit 1000. The cam follower 1038 and thedriven gear portion 1037 are arranged on a rear end portion of the outerperipheral surface of the drive frame unit 1000. The cam follower 1038engages with a cam groove formed on the inner peripheral surface of thefixed frame 900. The driven gear portion 1037 engages with a drive gear910 a joined to a drive shaft of the zooming motor unit 910 (see FIG.25, FIG. 26). By driving the zooming motor unit 910, the drive frameunit 1000 advances or retracts in the optical axis direction whilerotating about the optical axis AX. The drive frame unit 1000 includes:an ornamental ring 1010; a first drive frame 1020; and a second driveframe 1030. The detailed constitution of the drive frame unit 1000 isdescribed later.

The penetration cam frame 1100 is formed in a circular cylindricalshape. The penetration cam frame 1100 is arranged on an inner peripheralside of the drive frame unit 1000. The penetration cam frame 1100includes: a penetration cam groove 1106 which penetrates a wall(hereinafter, referred to as “peripheral wall”) of the penetration camframe 1100 which constitutes the circular cylinder in the radialdirection; rotation restricting grooves; lifting cam followers 1101; androtation restricting projections 1109. The penetration cam frame 1100 isheld on the drive frame unit 1000 in a rotatable manner relative to thedrive frame unit 1000 about the optical axis AX. The penetration camgroove 1106 penetrates the peripheral wall of the penetration cam frame1100 in the radial direction. The lifting cam followers 1101 are formedon an outer peripheral surface of the penetration cam frame 1100, andengage with the lifting cam grooves 1032 formed on the inner peripheralsurface of the drive frame unit 1000. The rotation restrictingprojections 1109 are arranged on a rear end portion of the outerperipheral surface of the penetration cam frame 1100, and engage withthe rotation restricting grooves formed on the inner peripheral surfaceof the fixed frame 900. With this configuration, the penetration camframe 1100 is movable in the optical axis direction relative to thefixed frame 900, while the rotation of the penetration cam frame 1100relative to the fixed frame 900 about the optical axis AX is restricted.

As shown in FIG. 28 and FIG. 29, the double-sided cam frame unit 1300includes: a double-sided cam frame 1310; and an ornamental frame 1320.The ornamental frame 1320 is fixed to the double-sided cam frame 1310.With this configuration, the ornamental frame 1320 is integrally formedwith the double-sided cam frame 1310. An outer peripheral surface 1320 oof the ornamental frame 1320 forms an external appearance surface whichcan be visually recognized from the outside. Accordingly, an externalappearance treatment such as hairline machining or blast machining isapplied to the outer peripheral surface of the ornamental frame 1320. Onthe other hand, an inner peripheral surface of the ornamental frame 1320is formed into a circular cylindrical surface having no unevenness. Thisis because that, in the lens barrel of this embodiment, the innerperipheral surface of the ornamental frame 1320 is not required to havea function of restricting the rotation of the first group unit 100 andthe like, and it is sufficient for the ornamental frame 1320 that theornamental frame 1320 has only a function of fixing the ornamental frame1320 per se to the double-sided cam frame 1310. The restricting of therotation of the first group unit 100 is performed by the rotationrestricting frame 1200 arranged on an inner peripheral side of thedouble-sided cam frame 1310. Accordingly, the ornamental frame 1320which is arranged on an outer peripheral side of the first group unit100 is not required to have a function of restricting the rotation ofthe first group unit 100. In view of the above, only the outerperipheral surface 1320 o of the ornamental frame 1320 is formed of asurface to which an external appearance treatment such as hairlinemachining or blast machining is applied, and an inner peripheral surface1320 i is formed of a circular cylindrical surface having theapproximately same diameter and having no unevenness. With thisconfiguration, when metal is selected as a material for forming theornamental frame 1320, the ornamental frame 1320 can be formed only bypress working and lathe machining. When a metal material is used,compared to the case where a resin material is used, the same strengthcan be acquired while reducing a thickness of the ornamental frame 1320.When an external appearance function is provided to the outer peripheralsurface of the ornamental frame 1320 and a rotation restricting functionis provided to the inner peripheral surface of the ornamental frame 1320as functions of the ornamental frame 1320, it is necessary to providethe structure where unevenness is formed on the inner peripheral side ofthe ornamental frame 1320 in the circumferential direction, that is, thestructure where the radius of the ornamental frame 1320 is not uniformover the entire length. Accordingly, milling, machining or the likebecomes necessary in addition to press working and lathe machining. Inthis case, a working cost is increased. As a method of providing thestructure where unevenness is formed on an inner peripheral surface of aproduct in a circumferential direction at a low cost, there has beenknown an injection molding method which uses a resin for forming theproduct. However, in this method, the outer peripheral surface is alsomade of a resin. Accordingly, there exists a drawback that the qualityof external appearance is deteriorated. As a method for overcoming sucha drawback, a method may be considered where the ornamental frame 1320is formed of two parts such that the outer peripheral surface is formedusing a metal material and the inner peripheral surface is formed usinga resin material. In this case, however, the number of parts isincreased so that a manufacturing cost is pushed up.

The present disclosure is made to cope with such a drawback. In thepresent disclosure, the lens barrel includes: the first frame (the firstgroup unit 100); the second frame (the double-sided cam frame 1310)which is arranged on an inner peripheral side of the first frame (thefirst group unit 100) and engages with the first frame (the first groupunit 100) by a cam mechanism; the third frame (the double-sided camframe 1310) which is arranged on an inner peripheral side of the secondframe (the double-sided cam frame 1310), engages with the first frame(the first group unit 100) by a rotation restricting mechanism, and isrotatable relative to the second frame (the double-sided cam frame1310); and the fourth frame (the ornamental frame 1320) which isarranged on an outer peripheral side of the first frame (the first groupunit 100), and integrally engages with the second frame (double-sidedcam frame 1310) in the optical axis direction. The fourth frame (theornamental frame 1320) is formed as a single part where the outerperipheral surface 1320 o is formed of a surface to which an externalappearance treatment is applied using secondary machining such ashairline machining or blast machining, and the inner peripheral surface1320 i is formed of a circular cylindrical surface having theapproximately uniform diameter over the whole length and having nounevenness.

The engagement between the double-sided cam frame 1310 and theornamental frame 1320 is described. In the present disclosure, thedouble-sided cam frame 1310 and the ornamental frame 1320 are integrallyjoined to each other both in the optical axis direction and in therotational direction (in the circumferential direction) at approximatelyrear end portions thereof in the optical axis direction. Thedouble-sided cam frame 1310 and the ornamental frame 1320 respectivelyhave optical-axis-direction restricting portions 1310 a, 1320 a,rotational direction restricting portions 1310 b, 1320 b, and radialdirection restricting portions 1310 c, 1320 c. By making these threekinds of restricting portions contact each other or engage with eachother respectively, the relative positions between the double-sided camframe 1310 and the ornamental frame 1320 are decided. In the presentdisclosure, the inner peripheral surface 1320 i of the ornamental frame1320 is constituted of a surface having no steps, and is continuouslyformed with the inner peripheral surface of the radial directionrestricting portion 1320 c while having the same diameter as the innerperipheral surface of the radial direction restricting portion 1320 c.The double-sided cam frame 1310 and the ornamental frame 1320 furtherinclude optical-axis-direction fixing portions 1310 d, 1320 d, androtational-direction fixing portions 1310 e, 1320 e respectively. Bymaking two kinds of fixing portions engage with each other respectively,the double-sided cam frame 1310 and the ornamental frame 1320 are fixedto each other in the respective directions. The optical-axis-directionrestricting portion 1320 a, the rotational direction restricting portion1320 b, the radial direction restricting portion 1320 c, theoptical-axis-direction fixing portion 1320 d, and the rotationaldirection fixing portion 1320 e are arranged between the outerperipheral surface 1320 o and the inner peripheral surface 1320 i, thatis, within a thickness range of the ornamental frame 1320. It may bepossible to adopt the structure where the double-sided cam frame 1310and the ornamental frame 1320 are integrally joined to each other in theoptical axis direction and are rotatably engageable with each other inthe rotational direction (circumferential direction). The ornamentalframe 1320 includes neither the rotation restricting mechanism nor thecam mechanism and the like and hence, the ornamental frame 1320 may beeither rotatable or non-rotatable relative to the double-sided cam frame1310. In this case, the double-sided cam frame 1310 and the ornamentalframe 1320 may be joined to each other by a known bayonet mechanism orthe like.

The double-sided cam frame 1310 is formed in a circular cylindricalshape. The double-sided cam frame 1310 is arranged on the innerperipheral side of the penetration cam frame 1100. The double-sided camframe 1310 includes cam grooves and cam followers. The cam grooves areformed on an inner peripheral surface and an outer peripheral surface ofthe double-sided cam frame 1310 respectively. The cam followers arearranged on a rear end portion of the outer peripheral surface of thedouble-sided cam frame 1310. The cam followers engage with penetrationcam grooves 1106 of the penetration cam frame 1100 and rotationrestricting grooves formed on an inner peripheral surface of the driveframe unit 1000. When the drive frame unit 1000 is rotated about theoptical axis AX, the rotation of the double-sided cam frame 1310relative to the drive frame unit 1000 is restricted. However, even whenthe drive frame unit 1000 is rotated about the optical axis AX, thedouble-sided cam frame 1310 advances or retracts in the optical axisdirection relative to the penetration cam frame 1100 due to the cammechanism constituted of the cam grooves and the cam followers of thepenetration cam frame 1100.

Returning to FIG. 3, the rotation restricting frame 1200 is formed in acircular cylindrical shape. The rotation restricting frame 1200 isarranged on an inner peripheral side of the double-sided cam frame unit1300. The rotation restricting frame 1200 has rotation restrictingprojections and rotation restricting slits 1220. The rotationrestricting projections are arranged on a front end portion of an outerperipheral surface of the rotation restricting frame 1200. The rotationrestricting slits 1220 penetrate a peripheral wall of the rotationrestricting frame 1200 in the radial direction. The rotation restrictingslits 1220 are arranged along the optical axis direction. The rotationrestricting frame 1200 is held in the double-sided cam frame unit 1300such that although the rotation of the rotation restricting frame 1200about the optical axis AX relative to the double-sided cam frame unit1300 is allowed, the movement of the rotation restricting frame 1200 inthe optical axis direction relative to the double-sided cam frame unit1300 is restricted.

The first group unit 100 holds the first lens group L1 for introducinglight into the inside of the lens barrel 2000 (see FIG. 2B). The firstgroup unit 100 is formed in a circular cylindrical shape. The firstgroup unit 100 includes: rotation restricting grooves; and camfollowers. The rotation restricting grooves of the first group unit 100are formed on an inner peripheral surface of the first group unit 100along the optical axis direction, and engage with the rotationrestricting projections of the rotation restricting frame 1200. The camfollowers of the first group unit 100 are arranged on a rear end portionof the inner peripheral surface. The cam followers of the first groupunit 100 engage with the cam grooves formed on the outer periphery ofthe double-sided cam frame 1310. When the double-sided cam frame 1310rotates about the optical axis AX, the first group unit 100 advances orretracts in the optical axis direction by the cam mechanism which isconstituted of the cam grooves and the cam followers of the double-sidedcam frame 1310. At this stage of the operation, the rotation of thefirst group unit 100 about the optical axis AX is restricted by therotation restricting frame 1200.

The second group unit 200 holds the second lens group L2 used forzooming. The second group unit 200 is formed in a circular disc shape,and is arranged on an inner peripheral side of the rotation restrictingframe 1200. The second group unit 200 has cam followers on an outerperiphery thereof. The cam followers of the second group unit 200 areinserted into the rotation restricting slits 1220 of the rotationrestricting frame 1200 and, at the same time, engage with the camgrooves formed on an inner periphery of the double-sided cam frame 1310.When the double-sided cam frame 1310 is rotated about the optical axisAX, the second group unit 200 advances or retracts in the optical axisdirection by the cam mechanism which is constituted of the cam groovesand the cam followers of the double-sided cam frame 1310. At this stageof the operation, the rotation of the second group unit 200 about theoptical axis AX is restricted by the rotation restricting frame 1200.

The third group unit 300 holds the third lens group L3 used for zoomingand the correction of blurring of an image. The third group unit 300 isformed in an approximately circular cylindrical shape, and is arrangedon an inner peripheral side of the rotation restricting frame 1200. Thethird group unit 300 has a flange portion on a rear end portion thereof.The third group unit 300 includes: cam followers 334; and rotationrestricting projections. The cam followers 334 of the third group unit300 are mounted on an outer peripheral surface of a front end portion ofthe third group unit 300 in an erected manner. The cam followers 334 areinserted into the rotation restricting slits 1220 of the rotationrestricting frame 1200 and, at the same time, engage with the camgrooves formed on the inner periphery of the double-sided cam frame1310. The rotation restricting projections of the third group unit 300are formed in a projecting manner in the outer peripheral direction fromthe rear end flange portion, and engage with the rotation restrictinggrooves formed on the inner peripheral surface of the penetration camframe 1100. When the double-sided cam frame 1310 is rotated about theoptical axis AX, the third group unit 300 advances or retracts in theoptical axis direction by being driven by the cam mechanism which isconstituted of the cam grooves and the cam followers of the double-sidedcam frame 1310, while the rotation of the third group unit 300 isrestricted by the penetration cam frame 1100.

The fourth group unit 400 holds the fourth lens group L4 used forzooming and focusing. The fourth group unit 400 is supported in amovable manner in the optical axis direction with respect to the masterflange unit 600, and is driven in the optical axis direction by thefocus motor unit 610. The focus motor unit 610 is a drive source forextending the fourth group unit 400. The fourth group unit 400 includes:a main guide portion; a sub guide portion; a spring contact portion; anda nut contact portion. The main guide portion restricts a position ofthe fourth group unit 400 in a plane orthogonal to the optical axis andthe inclination of the fourth group unit 400 with respect to the opticalaxis. The main guide portion engages with a fourth group guide shaftsuch that the fourth group unit 400 is movable in the optical axisdirection. The sub guide portion restricts the position of the fourthgroup unit 400 in a plane orthogonal to the optical axis together withthe main guide portion. A biasing spring which biases the fourth groupunit 400 frontwardly in the optical axis direction is brought intocontact with the spring contact portion. A nut is brought into contactwith the nut contact portion. The focus motor unit 610 includes: thenut; and a screw. The screw moves the nut in the optical axis directionby rotation. The focus motor unit 610 includes a screw feedingmechanism. When the screw is rotated by the rotation of the motor, thescrew feeding mechanism moves the nut in the optical axis direction.When the nut is moved in the optical axis direction by the screw feedingmechanism, the nut contact portion to which the nut is pushed by way ofthe biasing spring is moved in the optical axis direction. As a result,the fourth group unit 400 is moved in the optical axis direction.

The fifth group unit 500 holds the fifth lens group L5 used for zooming.The fifth group unit 500 is supported in a movable manner in the opticalaxis direction with respect to the master flange unit 600. The fifthgroup unit 500 is driven in the optical axis direction by a fifth groupdrive arm 520. As shown in FIG. 22, the fifth group drive arm 520includes: cam followers 523; rotational direction restricting portions525; and rotation restricting portions 521. The cam followers 523 engagewith the driving cam grooves 1036 of the drive frame unit 1000. Therotational direction restricting portions 525 engage with restrictingportions 902 of the fixed frame 900. The rotation restricting portions521 engage with guide grooves 1111 of the penetration cam frame 1100.When the drive frame unit 1000 is rotated about the optical axis AX, thefifth group drive arm 520 advances or retracts in the optical axisdirection by being driven by a cam mechanism constituted of the camgrooves and the cam followers 523 of the drive frame unit 1000. Therotation of the fifth group drive arm 520 is restricted by the fixedframe 900 and the penetration cam frame 1100.

The shutter unit 1400 is formed in a circular disc shape. The shutterunit 1400 is arranged on an inner peripheral side of the rotationrestricting frame 1200. The shutter unit 1400 includes: an innerdiameter opening portion; and cam followers formed on an outerperipheral surface thereof. The shutter unit 1400 also includes: adiaphragm mechanism; and a shutter mechanism. The diaphragm mechanismadjusts a size of a diameter of an opening by driving diaphragm blades.The shutter mechanism allows the transmission of light or shuts offlight by opening or closing shutter blades. The diaphragm mechanism canperform a drive control of the diaphragm blades in response to anelectric signal. The shutter mechanism can perform an open-close controlof the shutter blades in response to an electric signal. In the opticalsystem of the present disclosure, for miniaturizing the optical system,the shutter mechanism and the diaphragm mechanism are moved in theoptical axis direction independently from the lens group at the time ofzooming. The cam followers of the shutter unit 1400 are inserted intothe rotation restricting slits 1220 of the rotation restricting frame1200, and also engage with the cam grooves formed on an inner peripheralsurface of the double-sided cam frame 1310. The restriction of therotation of the shutter unit 1400 is performed by the rotationrestricting slits 1220 of the rotation restricting frame 1200 whichperforms the restriction of the rotation of the third group unit 300.When the double-sided cam frame 1310 is rotated about the optical axisAX, the shutter unit 1400 advances or retracts in the optical axisdirection by being driven by the cam mechanism constituted of the camgrooves and the cam followers of the double-sided cam frame 1310 whilethe rotation of the shutter unit 1400 is restricted by the rotationrestricting frame 1200.

The imaging element unit 700 includes an imaging element. The imagingelement converts light imaged on the imaging element by the first lensgroup L1 to the sixth lens group L6 into an electric signal.

The flexible printed circuit board 800 is a bendable printed circuitboard having flexibility. The flexible printed circuit board 800connects the zooming motor unit 910, the focus motor unit 610, and theshutter unit 1400 to an electric circuit on a main body side.

In the above-mentioned constitution, zooming and focusing can beperformed by moving the first lens group L1 to the sixth lens group L6in the optical axis direction by driving the zooming motor unit 910 andthe focus motor unit 610. To be more specific, at the time of zooming,that is, at the time of changing a focal length, the zooming motor unit910 and the focus motor unit 610 are driven. When the zooming motor unit910 is driven at the time of zooming, due to the above-mentioned cammechanism, the first group unit 100, the second group unit 200, theshutter unit 1400, the third group unit 300, and the fifth group unit500 are moved in the optical axis direction. When the focus motor unit610 is driven at the time of zooming, the fourth group unit 400 isdriven by the above-mentioned screw feeding mechanism so that the fourthgroup unit 400 is moved in the optical axis direction. At the time ofperforming the adjustment of focusing, that is, at the time of adjustingthe focal position, only the focus motor unit 610 is driven. When thefocus motor unit 610 is driven at the time of performing the adjustmentof focusing, the fourth group unit 400 is driven by the above-mentionedscrew feeding mechanism so that the fourth group unit 400 is moved inthe optical axis direction.

[3. Members Constituting Lens Barrel]

Members constituting the lens barrel are described in detail.

[3.1. Third Group Unit 300]

FIG. 4 is an exploded perspective view of the third group unit 300.

The third group unit 300 includes: a retracting lens frame unit 301; anOIS frame unit 302; and a third group frame unit 303.

[3.1.1. Retracting Lens Frame Unit 301]

The retracting lens frame unit 301 includes: a retracting lens frame310; a retracting lever portion 311; the third lens group L3; and athird group light blocking sheet 340.

The third lens group L3 is constituted of three lenses. The third lensgroup L3 is inserted into the retracting lens frame 310 from front andrear sides of the retracting lens frame 310, and is fixed by adhesion tothe retracting lens frame 310.

The third group light blocking sheet 340 is fixed to a rear surface ofthe retracting lens frame 310. The third group light blocking sheet 340is made of a resin having light blocking property, and blocks undesiredlight beams on an outer peripheral side of the third lens group L3.

[3.1.2. OIS Frame Unit 302]

The OIS frame unit 302 includes: an OIS frame 320; a yaw magnet 371; anda pitch magnet 372.

The yaw magnet 371 and the pitch magnet 372 are fixed to a rear surfaceof the OIS frame 320 by an adhesive agent. The yaw magnet 371 and thepitch magnet 372 are magnetized to two poles respectively.

A retracting shaft 324 is integrally formed on the OIS frame 320. Theretracting shaft 324 is inserted into a bearing portion 312 of theretracting lens frame 310.

A thrust spring 350 is mounted on the bearing portion 312 and theretracting shaft 324 in a state where the retracting shaft 324 isinserted into the bearing portion 312. With this configuration, theretracting lens frame unit 301 and the OIS frame unit 302 are biased inthe direction that the retracting lens frame unit 301 and the OIS frameunit 302 are brought into close contact with each other in the opticalaxis direction.

By mounting a coil-shaped rotation spring 360 on the OIS frame unit 302in such a state, the retracting lens frame unit 301 is biased in thedirection that the retracting lens frame unit 301 is rotated about thebearing portion 312 with respect to the OIS frame unit 302.

At the time of performing usual photographing, the third lens group L3of the retracting lens frame unit 301 is held at a position in thevicinity of the center position of the OIS frame unit 302 due to abiasing force of the rotation spring 360 and a biasing force of thethrust spring 350.

[3.1.3. Third Group Frame Unit 303]

The third group frame unit 303 includes: the third group frame 303; ayaw coil 381; a pitch coil 382; a pitch coil 383; a Hall element 384; ayoke 391; a yoke 392; a yoke 393; an OIS stopper 331; an OIS shaft 385;and three OIS balls 373.

As described above, the third group frame 330 engages with thepenetration cam frame 1100, the rotation restricting frame 1200, and thedouble-sided cam frame 1310.

The yaw coil 381, the pitch coil 382, and the pitch coil 383 are coilsfor driving the OIS frame unit 302. These coils are arranged on an innerperipheral side of the third group frame 330, and are fixed to a frontsurface of a mounting surface portion 339 of the third group frame 330orthogonal to the optical axis.

The Hall element 384 is a sensor for detecting the position of the OISframe unit 302. The Hall element 384 is fixed to the front surface ofthe mounting surface portion 339.

The OIS shaft 385 is a shaft for controlling the movement of the OISframe unit 302. The OIS shaft 385 has one end portion thereof fixed tothe front surface of the mounting surface portion 339 such that the OISshaft 385 is arranged parallel to the optical axis.

The yoke 391, the yoke 392, and the yoke 393 are fixed to a rear surfaceof the mounting surface portion 339 of the third group frame 330 atpositions where the yoke 391, the yoke 392 and the yoke 393 face the yawcoil 381, the pitch coil 382, and the pitch coil 383 in an opposedmanner respectively. The yoke 391, the yoke 392, and the yoke 393 areformed of a plated steel plate such that the yoke 391, the yoke 392, andthe yoke 393 are biased in the attracting direction by magnetisms of theyaw magnet 371 and the pitch magnet 372 of the OIS frame unit 302.

The OIS stopper 331 suppresses the movement of the OIS frame unit 302 inthe optical axis direction. That is, the OIS stopper 331 prevents theOIS frame unit 302 from being removed from the third group frame unit303.

Three OIS balls 373 are sandwiched and held between the OIS frame unit302 and the third group frame unit 303.

Due to the above-mentioned constitution, the OIS frame unit 302 issupported in a movable manner in a plane orthogonal to the optical axiswith respect to the third group frame unit 303.

Further, a U-shaped groove portion 321 is formed on the OIS frame 320.The U-shaped groove portion 321 engages with the OIS shaft 385 byfitting engagement. With this configuration, the direction of movementof the OIS frame unit 302 is restricted. To be more specific, withrespect to the third group frame unit 303, the OIS frame unit 302 canperform only the rotation about the OIS shaft 385 and the translationalmovement to the OIS shaft 385 in a plane orthogonal to the optical axis.

[3.1.4. Manner of Operation of OIS]

The manner of operation of the OIS is described in more detail withreference to FIG. 5A to FIG. 7B.

FIGS. 5A and 5B are constitutional views of the OIS actuator. FIG. 5A isa side view of the OIS actuator, and FIG. 5B is a front view of the OISactuator. The OIS actuator is constituted of: the yaw magnet 371; thepitch magnet 372; the yaw coil 381; the pitch coil 382; the pitch coil383; the yoke 391; the yoke 392; and the yoke 393 described above.

In FIGS. 5A and 5B, for the sake of brevity, the OIS actuator is shownin a state where the retracting lens frame 310, the OIS frame 320, thethird group frame 330 and the like are omitted.

The yaw coil 381 and the Hall element 384 are arranged on a rear side ofthe yaw magnet 371 with a slight gap formed therebetween. The yoke 391is arranged on a rear side of the yaw coil 381.

The pitch coil 382, the pitch coil 383, and the Hall element 384 arearranged on a rear side of the pitch magnet 372 with a slight gap formedtherebetween. The yoke 392 is arranged on a rear side of the pitch coil382. Further, the yoke 393 is arranged on a rear side of the pitch coil383.

The third lens group L3, the yaw magnet 371 and the pitch magnet 372 arefixed to the OIS frame 320. Accordingly, at the time of performing usualphotographing, when the third lens group L3 is moved, that is, when theOIS frame 320 is moved, the position of the yaw magnet 371 and theposition of the pitch magnet 372 with respect to the Hall element 384are changed. At this stage of the operation, a magnetic flux at theposition where the Hall element 384 is disposed is changed so that anoutput of the Hall element 384 is changed. Accordingly, by detecting anoutput of the Hall element 384, the position of the third lens group 13can be obtained.

When blurring of an image attributed to the camera shake or the likeoccurs at the time of performing photographing, by energizing the yawcoil 381, the pitch coil 382, and the pitch coil 383 so as to move thethird lens group L3 in the direction that the blurring of the image iscanceled, the blurring of the image can be canceled.

[3.1.5. Magnetic Attraction Force]

FIGS. 6A and 6B are explanatory views of the magnetic attraction of theOIS actuator. FIG. 6A is a side view, and FIG. 6B is a front view. InFIGS. 6A and 6B, for the sake of convenience, the third lens group L3,the yaw magnet 371, the pitch magnet 372, the yaw coil 381, the pitchcoil 382, the pitch coil 383, the Hall element 384 and the like areomitted.

The yoke 391, the yoke 392 and the yoke 393 are identical parts havingthe same shape.

The yoke 391, the yoke 392, and the yoke 393 are formed by blanking asteel plate using a press. As such a steel plate, a plated steel platemade of a ferromagnetic material is used. Accordingly, a magneticattraction force is acting between the yoke 391 and the yaw magnet 371.

The shape and arrangement of the yoke 391 according to this embodimenthave the following features (1), (2), and (3).

(1) A length of the yoke 391 in the lateral direction is larger than alength of the yaw magnet 371 in the lateral direction (the polarizationdirection of the magnet). To be more specific, the length of the yoke391 in the lateral direction is set such that end portions of the yawmagnet 371 in the lateral direction do not project outwardly frompositions inside the end portions of the yoke 391 in the lateraldirection by a predetermined amount even when the positionalrelationship between the yaw magnet 371 and the yoke 391 is relativelychanged in the lateral direction. The “predetermined amount” means alength by which even when the positional relationship between the yawmagnet 371 and the yoke 391 is relatively changed in the lateraldirection, the magnitude of a force acting in the lateral directionbetween the yoke 391 and the yaw magnet 371 fall within a range twice aslarge as the magnitude of a force acting between the yoke 391 and theyaw magnet 371 in the lateral direction when both the yoke 391 and theyaw magnet 371 are in a steady state, for example. By setting thepredetermined amount as described above, when the yoke 391 and the yawmagnet 371 are moved relative to each other, it is possible to suppressa sharp change (a sharp increase) in power consumption of the OISactuator.

(2) A length of the left end portion of the yoke 391 in the verticaldirection is larger than a length of the right end portion of the yoke391 in the vertical direction. With this configuration, the yoke 391 hasa trapezoidal shape.

(3) The yoke 391 is fixed in a state where the yoke 391 is intentionallydisplaced with respect to the yaw magnet 371 in the leftward direction.To be more specific, the yoke 391 is fixed such that the center of theyoke 391 in the lateral direction is positioned on a left side of thecenter of the yaw magnet 371 in the lateral direction.

Effects acquired by the above-mentioned features (1), (2) and (3) aredescribed.

Effects Acquired by the Feature (1)

In the case where the position of the yoke 391 and the position of theyaw magnet 371 are relatively displaced from each other in the lateraldirection from initial positions of the yoke 391 and the yaw magnet 371,a force acting between the movable yoke 391 and the fixed yaw magnet 371in the lateral direction can be weakened. The force acting between theyoke 391 and the yaw magnet 371 in the lateral direction when the endportions of the yaw magnet 371 in the N and S directions are positionedin the vicinity of the end portions of the yoke 391 becomes larger thana force acting between the yoke 391 and the yaw magnet 371 in thelateral direction when the end portions of the yaw magnet 371 in the Nand S directions are disposed at initial positions. In this embodiment,the length of the yoke 391 in the lateral direction is set larger thanthe length of the yaw magnet 371 in the lateral direction and hence, asdescribed above, even when the position of the yaw magnet 371 in thelateral direction is changed, it is possible to suppress a large changein the force acting in the lateral direction.

A force acting in the lateral direction impedes the movement of the OISframe 320. That is, such a force impedes the operation of the OIS.Accordingly, it is desirable that the force is as weak as possible. Onthe other hand, it is desirable that an attraction force acting in thelongitudinal direction is strong to some extent for stabilizing theposture of the retracting lens frame unit 301 and the posture of the OISframe unit 302.

In this embodiment, the length of the yoke 391 in the lateral directionis set approximately 1.5 times as large as the length of the yaw magnet371 in the lateral direction.

When the length of the yoke 391 in the lateral direction is setsubstantially equal to the length of the yaw magnet 371 in the lateraldirection, the force acting in the lateral direction becomes maximum.The force acting in the lateral direction becomes weak when the lengthof the yoke 391 in the lateral direction is either larger or smallerthan the length of the yaw magnet 371 in the lateral direction. On theother hand, the larger the length of the yaw magnet 371 in the lateraldirection, the stronger the attraction force becomes in the longitudinaldirection. Accordingly, to weaken the force acting in the lateraldirection while ensuring the attraction force in the longitudinaldirection, it is sufficient that the length of the yoke 391 in thelateral direction is set larger than the length of the yaw magnet 371 inthe lateral direction.

Effects Acquired by the Features (2), (3)

To make a force act on the third lens group L3 in one direction when thethird lens group L3 is held on the optical axis AX, the yoke 391 isformed in asymmetry in the lateral direction and is arranged inasymmetry with respect to the yaw magnet 371 in the lateral direction.

In FIG. 6, symbol f1 indicates an attraction force applied to the yawmagnet 371 by the yoke 391 (fixed to the third group frame 330), symbolf2 indicates an attraction force applied to the pitch magnet 372 by theyoke 392, and symbol f3 indicates an attraction force applied to thepitch magnet 372 by the yoke 393. The yaw magnet 371 and the pitchmagnet 372 are fixed to the OIS frame unit 302. Accordingly, a resultantforce of the attraction forces f1, f2 and f3 is applied to the OIS frameunit 302. Component forces obtained by dividing the resultant force ofthe attraction forces f1, f2 and f3 in the longitudinal direction, inthe vertical direction and in the lateral direction are expressed bysymbols F1, F2 and F3 in FIG. 6.

Symbol F1 is a force for pushing the OIS frame unit 302 in the rearwarddirection. It is preferable that the force F1 is strong to some extentfor stabilizing postures of the retracting lens frame unit 301 and theOIS frame unit 302.

Symbol F2 is a force pulling up the OIS frame unit 302 in the upwarddirection. When the digital camera 3000 is held in a horizontal-positionphotographing state, the force F2 becomes a force for lifting up theretracting lens frame unit 301 and the OIS frame unit 302 against thegravity (a force which pulls up the OIS frame unit 302 in the upwarddirection (hereinafter referred to as “magnetic coercive force” or“magnetic coercive force F2” when appropriate)).

The force F3 is a force which pushes the U-shaped groove portion 321 tothe OIS shaft 385 in the leftward direction. The U-shaped groove portion321 and the OIS shaft 385 have dimensional errors attributed toirregularities in manufacture respectively. The OIS frame 320 on whichthe U-shaped groove portion 321 is made of a resin, while the OIS shaft385 is made of metal and hence, a linear expansion coefficient of theOIS frame 320 and a linear expansion coefficient of the OIS shaft 385differ from each other. Accordingly, it is necessary to set a width ofthe U-shaped groove portion 321 larger than a diameter of the OIS shaft385 so as to form a gap therebetween even when both the U-shaped grooveportion 321 and the OIS shaft 385 are thermally inflated in a statewhere the OIS shaft 385 is fitted in the U-shaped groove portion 321. Onthe other hand, when the gap is formed between the U-shaped grooveportion 321 and the OIS shaft 385, rattling is liable to occur betweenthe U-shaped groove portion 321 and the OIS shaft 385. According to thisembodiment, the OIS frame unit 302 is biased in the leftward directionby the force F3 thus giving rise to a state where a side surface of theU-shaped groove portion 321 of the OIS frame 320 is pushed to the OISshaft 385. Accordingly, even when such a gap is formed between theU-shaped groove portion 321 and the OIS shaft 385, it is possible tosuppress the OIS frame unit 302 from being vibrated due to rattling, andit is also possible to suppress the deterioration of image blurringcorrection performance caused by the positional displacement of thethird lens group L3.

As shown in FIG. 5B, holes 391 a, 392 a, 393 a are formed at twopositions in the yokes 391, 392, 393 respectively. These holes 391 a,392 a, 393 a, however, are holes for positioning the third group frame330 and hence, a magnetic attraction force is minimally affected bythese holes.

Next, effects acquired by the magnetic coercive force F2 is described indetail.

FIGS. 7A and 7B are explanatory views showing the power consumption ofthe OIS actuator. FIG. 7A shows the instantaneous power consumption, andFIG. 7B shows the average power consumption.

In FIGS. 7A and 7B, a ratio of the magnetic coercive force F2 withrespect to a total mass of the OIS movable portions (the retracting lensframe unit 301, the OIS frame unit 302, the thrust spring 350, and therotation spring 360) (magnetic coercive force/weight of movableportions) is taken on an axis of abscissas. When the magnetic coerciveforce/weight of movable portions is “1”, this means that the totalweight of the OIS movable portions and the magnetic coercive force F2are equal.

As shown in FIG. 7A, along with the increase of the magnetic coerciveforce F2, the power consumption of the OIS actuator at the horizontalposition is lowered. This is because along with the increase of themagnetic coercive force F2, the OIS movable portion is lifted higher dueto the magnetic coercive force F2 and hence, the necessity of liftingthe OIS movable portion against the gravity is decreased. On the otherhand, in the vertical position photographing state, along with theincrease of the magnetic coercive force F2, power consumption isincreased. This is because it is necessary to generate a force forpulling down the OIS movable portion in the downward direction againstthe magnetic coercive force F2.

Usually, photographing is not performed either only in the horizontalposition or only in the vertical position. That is, photographing isperformed in both positions.

When the inventors investigated photographs displayed in a photographcontest for amateurs and photographs posted to photograph posting siteon Internet, 110 pieces (78.0%) of photographs are photographs taken ata horizontal position out of 141 pieces of photographs with respect tothe photographs displayed in the photograph contest for amateurs. 971pieces (83.5%) of photographs are photographs taken at a horizontalposition with respect to 1163 pieces of photographs with respect to thephotographs posted to the photograph posting site. Based on the resultof these investigations, it is estimated that a rate of photographs atthe horizontal position is approximately 70 to 90% of all photographsalthough the rate may differ depending on the use and a user of adigital camera.

On the other hand, with respect to a moving image, a screen of a monitor(a television receiver set, a personal computer or the like) with whicha user enjoys the moving image is horizontally elongated and hence, mostmoving images are taken at the horizontal position.

FIG. 7B shows an average power consumption when the rate ofhorizontal-position photographing is 70%, 80%, and 90%.

When the rate of horizontal position photographing is 70% and a rate ofmagnetic coercive force/movable part mass is 0.5 to 0.9, the averagepower consumption becomes 60% or less of the average power consumptionwhen there is no magnetic coercive force. When the rate of horizontalposition photographing is 90% or more, for example, the average powerconsumption takes a minimum value when the rate of magnetic coerciveforce/movable part mass is larger than 0.9, and becomes lower than theaverage power consumption when the rate of the horizontal positionphotographing is 70% or 80%.

As described above, by setting a magnetic coercive force and a movablepart mass such that a rate of magnetic coercive force/movable part massbecomes larger than 0.2, the average power consumption can be lowered soas to prolong a lifetime of a battery. It is more preferable to set amagnetic coercive force and movable part mass such that a rate ofmagnetic coercive force/movable part mass becomes 0.5 to 1.0. By settingthe magnetic coercive force and movable part mass in this manner, theaverage power consumption can be lowered and hence, a lifetime of abattery can be prolonged.

(Effects and the Like)

Hereinafter, the technical features, the effects and the like of theabove-mentioned constitution are described. Hereinafter, constitutionalelements in claims and constitutional elements in the embodiment aredescribed in the form of “constitutional elements in claims(constitutional elements in embodiment)”. However, this form ofexpression is provided for facilitating the understanding of thecorrespondence between the constitutional elements in claims and theconstitutional elements in the embodiment, and does not intend to limitthe constitutional elements in claims to the constitutional elementsdescribed in the embodiment.

The lens barrel of the present disclosure includes the lens frame (OISframe 320) which holds the lens (the third group lens L3), and theholding frame (the third group frame 330) which holds the lens frame(OIS frame 320) in a state where the lens frame (OIS frame 320) ismovable in a plane orthogonal to the optical axis. A biasing means whichgenerates a force in the direction that the lens frame (OIS frame 320)is lifted up against the gravity is provided to at least the holdingframe (third group frame 330) out of the holding frame (third groupframe 330) and the lens frame (OIS frame 320).

With this configuration, the lens frame (OIS frame 320) is lifted upagainst the gravity by the biasing means and hence, a force for liftingup the lens frame (OIS frame 320) against the gravity can be reduced atthe time of operating the OIS frame. Accordingly, the power consumptionof the lens barrel can be reduced.

In the present disclosure, the biasing means includes: the magnets (theyaw magnet 371, the pitch magnet 372) mounted on the lens frame (the OISframe 320), and the yokes (the yoke 391, the yoke 392, the yoke 393)which are mounted on the holding frame (the third group frame 330) atpositions where the yokes face the magnets (the yaw magnet 371, thepitch magnet 372) in an opposed manner in the optical axis directionrespectively. The yokes (the yoke 391, the yoke 392, the yoke 393) arearranged on the holding frame (third group frame 330) and the shapes ofthe yokes (yoke 391, yoke 392, yoke 393) are set such that, in a statewhere the lens (the third group lens L3) is positioned at the center ofthe optical axis, the yokes (the yoke 391, the yoke 392, the yoke 393)are magnetically attracted in the predetermined directions in a planeorthogonal to the optical axis by the magnets (the yaw magnet 371, thepitch magnet 372).

With this constitution, the biasing means can be formed using themagnets, the yokes and the like.

In the present disclosure, the yokes (the yoke 391, the yoke 392, theyoke 393) are arranged on the holding frame (the third group frame 330)and the shapes of the yokes (the yoke 391, the yoke 392, the yoke 393)are set such that the optical axis of the lens (the third group lens L3)is positioned below the optical axis of the lens barrel by apredetermined amount.

With this constitution, the power consumption of the lens barrel can bereduced when vertical-position photographing is included in allphotographing by a predetermined rate.

In the present disclosure, a value obtained by dividing the force F2 ofthe biasing means in the lifting-up direction by the weight of the lensframe (the OIS frame 320) and the members (the OIS movable portion (theretracting lens frame unit 301, the OIS frame unit 302, the thrustspring 350, the rotation spring 360)) mounted on the lens frame (the OISframe 320) is set larger than 0.5.

By setting the force F2 in this manner, the power consumption of thelens barrel can be substantially halved.

In the present disclosure, the yokes (the yoke 391, the yoke 392, theyoke 393) are formed into a trapezoidal shape, and are arranged suchthat the direction orthogonal to the bottom side of the trapezoidalshape and the NS direction of the magnet (the yaw magnet 371, the pitchmagnet 372) agree with each other.

With this constitution, it is possible to generate a force directed inthe horizontal direction (the lateral direction) of the imaging device.

(Another Example of OIS Actuator)

In the above-mentioned example, the forces F1, F2, F3 in the respectivedirections are realized by a magnetic force generated between the pitchmagnet 372 and the yoke 392, a magnetic force generated between thepitch magnet 372 and the yoke 393, and a magnetic force generatedbetween the yaw magnet 371 and the yoke 391. However, these forces canbe also realized by making use of an elastic force of a mechanicalspring by arranging the mechanical spring or the like between the OISframe 320 and the third group frame 330. Hereinafter, an example wherethe mechanical spring is used is described with reference to FIGS. 30Aand 30B. In this example, the description of parts identical with theparts described above is omitted when appropriate.

FIGS. 30A and 30B are constitutional views showing another example ofthe OIS actuator. FIG. 30A is a side view, and FIG. 30B is a front view.The OIS actuator is constituted of: a yaw magnet 371; a pitch magnet372; a yaw coil 381; a pitch coil 382; a pitch coil 383; a spring 387;and a spring 388. That is, in this example, the spring 387 and thespring 388 are provided in place of the yoke 391, the yoke 392, and theyoke 393 of the example described above.

The spring 387 is arranged on a left side of a third lens group L3 andbelow the yaw magnet 371 and the yaw coil 381. The spring 387 is ahelical spring. An annular-shaped movable-side spring hook portion 387 ais formed on a front end side of the spring 387. The movable-side springhook portion 387 a engages with a spring engaging portion formed on anOIS frame 320. An annular-shaped fixed-side spring hook portion 387 b isformed on a rear end side of the spring 387. The fixed-side spring hookportion 387 b engages with a spring engaging portion formed on a thirdgroup frame 330. Although not particularly shown in the drawing, thespring engaging portions of the OIS frame 320 and the third group frame330 may have any constitution provided that the movable-side spring hookportion 387 a and the fixed-side spring hook portion 387 b areengageable with the spring engaging portions respectively.

The spring 388 is arranged on a right side of the third lens group L3.The spring 388 is a helical spring. An annular-shaped movable-sidespring hook portion 388 a is formed on a front end side of the spring388. The movable-side spring hook portion 388 a engages with a springengaging portion formed on the OIS frame 320. An annular-shapedfixed-side spring hook portion 388 b is formed on a rear end side of thespring 388. The fixed-side spring hook portion 388 b engages with aspring engaging portion formed on the third group frame 330. Althoughnot particularly shown in the drawing, the spring engaging portions ofthe OIS frame 320 and the third group frame 330 may have any structureprovided that the movable-side spring hook portion 388 a and thefixed-side spring hook portion 388 b are engageable with the springengaging portions respectively.

The spring 387 and the spring 388 are arranged in an inclined mannersuch that a rear end side is positioned above a front end side.Accordingly, the spring engaging portions of the third group frame 330are arranged above (at positions higher than) the spring engagingportions of the OIS frame 320 in the vertical direction of the camerabarrel.

The spring 388 is arranged above the spring 387 in the verticaldirection of the camera barrel. Accordingly, in the vertical directionof the camera barrel, the spring engaging portions for the spring 388 onthe third group frame 330 and the OIS frame 320 are arranged above (atthe positions higher than) the spring engaging portions for the spring387 on the third group frame 330 and the OIS frame 320.

By arranging the spring 387 and the spring 388 as described above,forces f1 a, f1 b directed toward an oblique rear and upper side can beapplied to the third group frame 330 using the spring 387 and the spring388. Component forces obtained by dividing a resultant force of theforce f1 a and the force f1 b as a force in the longitudinal directionand a force in the vertical direction are expressed by symbols F1, F2 inFIGS. 30A and 30B respectively.

The force F1 is a force which pushes the OIS frame unit 302 in therearward direction in the same manner as the force F1 in theabove-mentioned example.

The force F2 is a force which lifts up the OIS frame unit 302 in theupward direction in the same manner as the force F2 in theabove-mentioned example. This force corresponds to the magnetic coerciveforce in the above-mentioned example.

Accordingly, also in this example, the effects substantially equal tothe effects attributed to the forces F1, F2 described in theabove-mentioned example can be acquired.

[3.1.6. Method of Assembling Retracting Lens Frame Unit 301 and OISFrame Unit 302 into Third Group Frame Unit 303]

FIGS. 8A and 8B are views showing a method of assembling the retractinglens frame unit 301 and the OIS frame unit 302 into the third groupframe unit 303. FIG. 8A is a view showing a state taken in the course ofthe assembling operation, and FIG. 8B is a view showing a state afterthe assembling operation.

The OIS frame 320 includes a leaning projecting portion 322 whichprojects toward an outer peripheral side (see FIG. 4). The third groupframe 330 has a penetration window portion 332 which penetrates theperipheral wall of the third group frame 330 in the radial direction(see FIG. 4).

As shown in FIG. 8A, at the time of assembling, the retracting lensframe unit 301 and the OIS frame unit 302 are assembled into the threegroup frame unit 303 in a state where the retracting lens frame unit 301and the OIS frame unit 302 are inclined with respect to the optical axisdirection. At this stage of operation, the leaning projecting portion322 is inserted into the penetration window portion 332.

As shown in FIG. 8B, after assembling, the leaning projecting portion322 penetrates the penetration window portion 332, and a portion of theleaning projecting portion 322 projects to a more outer peripheral sidethan the outer peripheral surface of the peripheral wall of the thirdgroup frame unit 303. Further, the OIS stopper 331 is fixed to a portionof the third group frame 330 on a side substantially opposite to thepenetration window portion 332 in the radial direction (a positionspaced apart by approximately 180 degrees in the circumferentialdirection) with the center of the third group frame 330 sandwichedtherebetween such that a predetermined gap is formed between the OISstopper 331 and an OIS stopper contact surface 323 (see FIG. 4) of theOIS frame 320 in the optical axis direction. With this constitution,there is no possibility that the OIS frame 320 is removed from the thirdgroup frame 330 in the optical axis direction.

[3.1.7. Relationship between Third Group Unit 300 and RotationRestricting Frame 1200]

Hereinafter, the relationship between the third group unit 300 and therotation restricting frame 1200 is described with reference to FIG. 9and FIGS. 10A and 10B.

FIG. 9 is a perspective view showing the relationship between the thirdgroup unit 300 and the rotation restricting frame 1200.

FIGS. 10A and 10B are a side view and a cross-sectional view showing astate where the third group unit 300 and the rotation restricting frame1200 are assembled to each other. FIG. 10A is a side view, and FIG. 10Bis a cross-sectional view of the third group frame 330 and the rotationrestricting frame 1200 taken at a position corresponding to the camfollowers 334.

The third group frame 330 of the third group unit 300 has the camfollowers 334, supporting ribs 335, and reinforcing ribs 336. The thirdgroup frame 330 has the flange portion on the rear end portion thereof,and is formed into an approximately circular cylindrical shape. The camfollowers 334 are mounted on the outer peripheral surface of the frontend portion of the third group frame 330 in an erected manner. Thesupporting ribs 335 and the reinforcing ribs 336 are formed on theperipheral wall of the third group frame 330 in a projecting manner inthe outer peripheral direction.

The rotation restricting frame 1200 has the rotation restricting slits1220, supporting grooves 1230, and reinforcing grooves 1240. Therotation restricting frame 1200 is formed in an approximately circularcylindrical shape. The rotation restricting frame 1200 is arranged onthe outer peripheral side of the third group frame 330. The rotationrestricting slits 1220 penetrate the peripheral wall of the rotationrestricting frame 1200 in the radial direction. The rotation restrictingslits 1220 are formed along the optical axis direction, and rear endportions of the rotation restricting slits 1220 are opened. Thesupporting grooves 1230 and the reinforcing grooves 1240 are formed onthe inner peripheral surface of the rotation restricting frame 1200along the optical axis direction.

As shown in FIG. 10B, the cam followers 334 engage with the rotationrestricting slits 1220 by fitting engagement. The supporting ribs 335engage with the supporting grooves 1230 by fitting engagement. Thereinforcing ribs 336 engage with the reinforcing grooves 1240 by fittingengagement. With respect to the third group frame 330 and the rotationrestricting frame 1200, in the circumferential direction, onlycircumferential portions of the respective frames 330, 1200 which aredisposed within ranges T1 to T6 are brought into contact with each otherand are slidable relative to each other in such a state. A gap of anapproximately 0.05 to 0.1 mm is formed between the third group frame 330and the rotation restricting frame 1200 such that the third group frame330 and the rotation restricting frame 1200 are not brought into contactwith each other at positions other than the portions disposed in theranges T1 to T6. To be more specific, the cam followers 334 and therotation restricting slits 1220 are brought into contact with eachother, and the supporting ribs 335 and the supporting grooves 1230 arebrought into contact with each other. On the other hand, a gap is formedbetween the reinforcing ribs 336 and the reinforcing grooves 1240respectively.

The rear end portions of the rotation restricting slits 1220 are opened.Accordingly, the rotation restricting frame 1200 in a single form iseasily deformed due to opening of rear end portions of the rotationrestricting slits 1220 in the circumferential direction, the deflectionof the rotation restricting slits 1220 in the radial direction or thelike. In this embodiment, the structure is adopted where peripheralportions of the rotation restricting slits 1220 are sandwiched betweenthe cam followers 334 and the supporting ribs 335 of the third groupframe 330 in the circumferential direction as well as in the radialdirection and hence, such a deformation can be prevented. Accordingly,even when the rear end portions of the rotation restricting slits 1220are opened, a drawback attributed to opening of the rear end portions ofthe rotation restricting slits 1220 minimally occurs. Further, the camfollowers 334 can be inserted into the rotation restricting slits 1220from an opening end side of the rotation restricting slits 1220 andhence, the degree of freedom in assembling can be increased. Further,the cam followers 334 are slidable to positions in the vicinity of theopening ends of the rotation restricting slits 1220 and hence, therelative stroke between the third group frame 330 and the rotationrestricting frame 1200 in the optical axis direction can be extendedwhereby the length of the barrel in a collapsed state (hereinafterreferred to as “collapsed length” when appropriate) can be shortened.

[3.1.8. Retracting Operation of OIS Lens]

Hereinafter, a retracting operation of the OIS lens is described withreference to FIG. 9 to FIG. 12C.

FIGS. 11A and 11B are views showing a retracting operation of theretracting lens frame unit 301. FIG. 11A shows a photographing state,and FIG. 11B shows a collapsed state.

FIGS. 12A to 12C are views showing the relationship between the thirdgroup unit 300 and the rotation restricting frame 1200. FIG. 12A is afront view, FIG. 12B is a cross-sectional view taken along a line A-A inFIG. 12A, and FIG. 12C is a partially enlarged view of FIG. 12B.

As shown in FIG. 9, the rotation restricting frame 1200 has a retractingrib 1210 and a retracting cam groove 1250. The retracting rib 1210 isformed in a rearwardly extending manner from a front side in the opticalaxis direction more on an inner peripheral side than the innerperipheral surface of the rotation restricting frame 1200. A retractingcam surface 1211 which is obliquely cut is formed on a rear end portionof the retracting rib 1210. The retracting cam groove 1250 is formed onthe inner peripheral surface of the rotation restricting frame 1200, andis formed such that a width and a depth of the retracting cam groove1250 are gradually increased toward a rear side. Further, as shown inFIG. 12B, a wall portion 333 which projects toward an outer peripheralside is formed on the third group frame 330 at a position correspondingto the retracting rib 1210 of the rotation restricting frame 1200.

A size and a shape of the retracting rib 1210 are set such that theretracting cam surface 1211 (see FIG. 12B) is brought into contact withthe retracting lever portion 311 of the retracting lens frame 310 asshown in FIG. 11B in a collapsed state, and is not brought into contactwith the retracting lever portion 311 in a photographing state. A sizeof the retracting cam groove 1250 is set such that the retracting camgroove 1250 is brought into contact with the leaning projecting portion322 of the OIS frame 320 in a collapsed state but is not brought intocontact with the leaning projecting portion 322 in a photographingstate.

In a collapsed state shown in FIG. 11B, the whole OIS frame 320 is movedtoward a right upper side when the leaning projecting portion 322 ispushed in the X1 direction by the retracting cam groove 1250 of therotation restricting frame 1200 (see FIG. 9). Simultaneously, theretracting lens frame 310 is moved toward an upper side while rotatingabout the retracting shaft 324 when the retracting lever portion 311 ispushed in the X2 direction by the retracting cam surface 1211 of therotation restricting frame 1200. As a result, as shown in FIG. 12A, in acollapsed state, a space portion P is formed in a center portion of thethird group unit 300. In this embodiment, in a collapsed state, thefourth group unit 400 and a portion of the fifth group unit 500 areconfigured to be inserted into the space portion P. With thisconstitution, the length of the barrel in a collapsed state can beshortened.

Although the third group frame 330 is arranged on the inner peripheralside of the rotation restricting frame 1200 as described above, as shownin FIG. 12B, the wall portion 333 projects toward the outer peripheralside and hence, the retracting rib 1210 of the rotation restrictingframe 1200 is arranged more on an inner peripheral side than the wallportion 333.

When the retracting ribs are arranged on the outer peripheral side ofthe third group frame 330 contrary to the above-mentioned constitution,for example, it is necessary to form a hole in the peripheral wall ofthe third group frame 330 for enabling the contacting of the retractinglever portion 311 with the retracting rib. However, when such a hole isformed in the peripheral wall of the third group frame 33, there arisesa possibility that undesired light enters the inside of the barrel fromthe outer peripheral side of the third group frame 330 and adverselyinfluences an image. In this embodiment, by arranging the retracting rib1210 more on an inner peripheral side than the wall portion 330 of thethird group frame 330 as described above, it is unnecessary to form theabove-mentioned hole in the peripheral wall of the third group frame330. Accordingly, it is possible to prevent such a phenomenon thatundesired light enters the inside of the barrel from the outerperipheral side of the third group frame 330 and adversely influences animage.

As shown in FIGS. 12B and 12C, a gap W is formed between the OIS frame320 and the third group frame 330. In the OIS frame 320 and the thirdgroup frame 330, surfaces 324 a, 330 a which face each other in anopposed manner and may be brought into contact with each other arereferred to as “contact surfaces”. At the time of photographing wherethe lens barrel is extended, there is no possibility that the contactsurfaces 324 a, 330 a are brought into contact with each other. On theother hand, in a collapsed state of the lens barrel, a load is appliedto the retracting lever portion 311 of the retracting lens frame 310 bythe retracting cam surface 1211 of the rotation restricting frame 1200so that the contact surfaces 324 a, 330 a are brought into contact witheach other. By providing the contact surfaces 324 a, 330 a in thismanner, a stress which is applied to ball supporting portions of the OISballs 373 at the time of performing a retracting operation can bedispersed. With this constitution, it is possible to prevent thesubsequent formation of the dents on the ball supporting portions andthe deterioration of OIS performance attributed to the subsequentformation of the dents. When the retracting lever portion 311 is pushed,the OIS frame 320 is inclined with respect to the optical axis. However,since the contact surfaces 324 a, 330 a are brought into contact witheach other, the OIS frame 320 is not inclined any more. Accordingly, theretracting operation can be performed in a stable manner.

[3.2. Drive Frame Unit]

FIG. 13A is an exploded perspective view of the drive frame unit 1000.FIG. 13B is a view of a second drive frame 1030 as viewed from an outerperipheral side.

As shown in FIG. 13A, the drive frame unit 1000 includes: the ornamentalring 1010; a first drive frame 1020; and a second drive frame 1030. Theornamental ring 1010 is a part providing an external appearance to thebarrel, and is formed in a circular cylindrical shape. The ornamentalring 1010 is a press-formed product made of aluminum. To be morespecific, cutting is applied to a surface of the ornamental ring 1010and, thereafter, alumite treatment and coloring are applied to thesurface of the ornamental ring 1010.

The first drive frame 1020 is formed in a circular cylindrical shape.Three bayonet ribs 1022 and three bayonet ribs 1023 are formed on theinner peripheral surface of the first drive frame 1020 at pitches ofapproximately 120° in the circumferential direction. Further, a radialdirection restricting portion 1025 is formed on the inner peripheralsurface of the first drive frame 1020. Three rotation restrictinggrooves 1024 are formed on the inner peripheral surface of the firstdrive frame 1020 along the optical axis direction at pitches ofapproximately 120° in the circumferential direction. Three projections1020 a are formed on a rear end portion of the first drive frame 1020 atpitches of approximately 120° in the circumferential direction. Theprojections 1020 a extend rearwardly in the optical axis direction.

The ornamental ring 1010 and the first drive frame 1020 are integrallyjoined to each other by using an adhesive agent or the like.

The second drive frame 1030 is formed in a circular cylindrical shape.The lifting cam groove 1032, the lifting cam followers 1033, the liftingcam followers 1034, a radial direction restricting portion 1039, and therotation restricting groove 1035 are formed on an inner peripheralsurface of the second drive frame 1030. The rotation restricting groove1035 is formed along the optical axis direction. Three notched-shapedrecessed portions 1030 a are formed on a front end portion of the seconddrive frame 1030. The cam followers 1038 and the driven gear portion1037 are formed on an outer peripheral surface of the second drive frame1030.

Rotation restricting portions 1021 are formed on side portions of theprojections 1020 a of the first drive frame 1020 in the circumferentialdirection, and rotation restricting portions 1031 are formed on sideportions of the recessed portions 1030 a of the second drive frame 1030in the circumferential direction. The rotation restricting portions 1021and the rotation restricting portions 1031 are respectively brought intocontact with each other in a state where the rotation restrictingportions 1021 and the rotation restricting portions 1031 are assembledto each other. With this constitution, the relative rotation between thefirst drive frame 1020 and the second drive frame 1030 about the opticalaxis AX is restricted. However, the first drive frame 1020 and thesecond drive frame 1030 are movable relative to each other in theoptical axis direction.

Three driving cam grooves 1036 are formed on the inner peripheralsurface of the second drive frame 1030. Three driving cam grooves 1036are arranged close to each other. The driving cam grooves 1036 engagewith the cam followers 523 of the fifth group drive arm 520 for drivingthe fifth group lens frame 510 (see FIG. 22).

The driving cam grooves 1036 and the lifting cam groove 1032 have thesubstantially same depth (in the radial direction). The driving camgrooves 1036 and the lifting cam groove 1032 are arranged in a partiallyintersecting manner. A circumferential length of the lifting camfollower 1101 (see FIG. 3 and FIG. 4) of the penetration cam frame 1100which engages with the lifting cam groove 1032 is set larger than agroove width of the driving cam groove 1036. Accordingly, even when thelifting cam follower 1101 is located at the position where the drivingcam groove 1036 and the lifting cam groove 1032 intersect with eachother, the lifting cam follower 1101 is smoothly movable along thelifting cam groove 1032 without being removed or caught by the drivingcam grooves 1036.

As shown in FIG. 24, the cam followers 523 are engageable with thedriving cam grooves 1036. Three cam followers 523 are arranged close toeach other. Accordingly, even when one cam follower 523 out of three camfollowers 523 is moved to the intersection between the driving camgroove 1036 and the lifting cam groove 1032, at least one cam follower523 out of remaining two cam followers 523 engages with the driving camgroove 1036. Accordingly, the fifth group drive arm 520 is smoothlymovable along the driving cam groove 1036 without being removed from thesecond drive frame 1030 or without being caught by the lifting camgroove 1032.

Returning to FIG. 13B, the cam followers 1038 engage with the cam grooveformed on the inner peripheral surface of the fixed frame 900. Thedriven gear portion 1037 engages with the zooming motor unit 910 by wayof a gear. The driven gear portion 1037 is formed such that a region (ameshing portion) used in a collapsed state is positioned on a front sideof the driven gear portion 1037, and a region (a meshing portion) usedin a telescopic state is positioned on a rear side of the driven gearportion 1037. The second drive frame 1030 is extendable from the fixedframe 900 and is rotatable with respect to the fixed frame 900 by beingdriven by the driven gear portion 1037. Accordingly, the cam grooveformed on the inner peripheral surface of the fixed frame 900 is formedcorresponding to the driven gear portion 1037. With this constitution, alength of the drive gear 910 a used in the zooming motor unit 910 can beshortened. Further, as shown in FIG. 26, the region (the meshingportion) of the driven gear portion 1037 used in a telescopic stateoverlaps with the flange portion 1100 a formed on the rear end of thepenetration cam frame 1100 as viewed in the radial direction (see FIG.26). Accordingly, by avoiding the formation of the driven gear portion1037 in the region (the meshing portion) of the driven gear portion 1037used in a telescopic state, that is, a region in the vicinity of therear end portion of the second drive frame 1030 as much as possible, theflange portion 1100 a can be formed largely on the rear end of thepenetration cam frame 1100, and the flange portion 1100 a can be formedin a wide range. Further, the penetration cam frame 1100 can ensure astrength thereof and hence, the penetration cam frame 1100 is minimallybroken by an external force such as falling. Still further, a totallength of the lens barrel in a collapsed state can be further shortened.

When the second drive frame 1030 is driven by the zooming motor unit910, the cam followers 1038 are moved along the cam grooves (not shownin the drawing) of the fixed frame 900. With this constitution, thesecond drive frame 1030 advances or retracts in the optical axisdirection while rotating about the optical axis AX.

As described previously, the rotation restricting portions 1031 arebrought into contact with the rotation restricting portions 1021 of thefirst drive frame 1020. Accordingly, the first drive frame 1020 isrotated with respect to the fixed frame 900 along with the rotation ofthe second drive frame 1030.

[3.3. Penetration Cam Frame]

FIG. 14 is a perspective view of the penetration cam frame 1100.

The penetration cam frame 1100 is formed in a circular cylindricalshape. The penetration cam frame 1100 is arranged on the innerperipheral side of the drive frame unit 1000. Three lifting camfollowers 1101, three lifting cam grooves 1102, three lifting camgrooves 1103, three bayonet grooves 1104, three bayonet grooves 1105,three radial direction restricting portions 1112, and three radialdirection restricting portions 1113 are formed on the outer peripheralsurface of the penetration cam frame 1100 at pitches of approximately120° in the circumferential direction respectively. Further, threepenetration cam grooves 1106 are formed on the penetration cam frame1100 at pitches of approximately 120° in the circumferential direction.The penetration cam grooves 1106 penetrate the peripheral wall of thepenetration cam frame 1100 in the radial direction.

The lifting cam followers 1101 are formed on the penetration cam frame1100 in a projecting manner in the outer peripheral direction. Thelifting cam follower 1101 is formed in a shape which is obtained byarranging two frustoconical bases parallel to each other in thecircumferential direction and by connecting two frustoconical bases toeach other. The lifting cam followers 1101 engage with the lifting camgrooves 1032 of the drive frame unit 1000.

The lifting cam grooves 1102 and the lifting cam grooves 1103 are formedon the outer peripheral surface of the penetration cam frame 1100. Thelifting cam grooves 1102 engage with the lifting cam followers 1033 ofthe second drive frame 1030. A slight gap may be formed between thelifting cam grooves 1102 and the lifting cam followers 1033. The liftingcam grooves 1103 engage with the lifting cam followers 1034 of thesecond drive frame 1030. A slight gap may be formed between the liftingcam grooves 1103 and the lifting cam followers 1034. The radialdirection restricting portions 1112 and the radial direction restrictingportions 1025 engage with each other and hence, the movement of thefirst drive frame 1020 in the radial direction with respect to thepenetration cam frame 1100 is restricted. The radial directionrestricting portions 1113 and the radial direction restricting portions1039 engage with each other and hence, the movement of the second driveframe 1030 in the radial direction with respect to the penetration camframe 1100 is restricted.

The bayonet grooves 1104 and the bayonet grooves 1105 are formed on theouter peripheral surface of the peripheral wall of the penetration camframe 1100. The bayonet grooves 1104 and the bayonet grooves 1105 engagewith the bayonet ribs 1022 and the bayonet ribs 1023 of the first driveframe 1020 respectively. In this embodiment, the lifting cam groove 1102and the bayonet groove 1105, and the lifting cam groove 1103 and thebayonet groove 1105 are formed such that portions of these grooves areused in common. However, the respective grooves may be formedindependently from each other.

[3.4. Relationship Among First Drive Frame 1020, Second Drive Frame 1030and Penetration Cam Frame 1100]

FIG. 15A and FIG. 15B are developed views (schematic views) showing therelationship among the first drive frame 1020, the second drive frame1030 and the penetration cam frame 1100.

FIG. 15A(a) is a developed view of the first drive frame 1020 and thesecond drive frame 1030 as viewed from an inner peripheral side. FIG.15A(b) is a perspective developed view of the penetration cam frame 1100as viewed from an inner peripheral side. FIG. 15B(a) is a view showingthe relationship among the frames in a collapsed state. FIG. 15B(b) is aview showing the relationship among the frames in a telescopic state. InFIGS. 15B(a), 15B(b), several symbols are omitted for the sake ofconvenience of explanation.

As described previously, when the second drive frame 1030 is rotatablydriven by the zooming motor unit 910, the first drive frame 1020 isrotated together with the second drive frame 1030. In such an operation,due to the relationship between the first and second drive frames 1020,1030 and the penetration cam frame 1100, the first drive frame 1020 andthe second drive frame 1030 make different movements in the optical axisdirection.

Hereinafter, the movements of the first drive frame 1020 and the seconddrive frame 1030 are specifically described. The movements are describedwith reference to FIGS. 25, 26 together with FIGS. 15A, 15B. FIG. 25 isa cross-sectional view of the lens barrel 2000 in a collapsed state.FIG. 26 is a cross-sectional view of the lens barrel 2000 in atelescopic state.

As shown in FIGS. 25, 26, in the second drive frame 1030, the liftingcam groove 1032 engages with the lifting cam follower 1101 of thepenetration cam frame 1100. In the penetration cam frame 1100, therotation restricting projection 1109 arranged on a rear end portionengages with a rotation restricting groove (not shown in the drawing) ofthe fixed frame 900. The rotation restricting groove of the fixed frame900 is formed along the optical axis direction.

When the second drive frame 1030 is rotated with respect to the fixedframe 900, as shown in FIGS. 15B(a), 15B(b), the lifting cam follower1101 is moved along the lifting cam groove 1032. As a result, as shownin FIGS. 25, 26, the penetration cam frame 1100 is moved toward a frontside relative to the second drive frame 1030. That is, the penetrationcam frame 1100 is brought into a telescopic state shown in FIG. 26 froma collapsed state shown in FIG. 25. In the same manner as the liftingcam follower 1101, the lifting cam follower 1033 and the lifting camfollower 1034 move relative to the lifting cam groove 1102 and thelifting cam groove 1103 respectively. The lifting cam follower 1033 andthe lifting cam follower 1034 are cam followers provided for reinforcingthe lifting cam follower 1101.

The lifting cam groove 1102 and the lifting cam follower 1033 of thesecond drive frame 1030 or the lifting cam groove 1103 and the liftingcam follower 1034 of the second drive frame 1030 are formed with aslight gap therebetween in a normal operation. Although such a gap isirrelevant to the operation of the barrel, when a large external forceis applied to the lens barrel due to falling of the barrel or the like,the gap assists the engagement between the lifting cam follower 1101 andthe lifting cam groove 1032 thus preventing disengagement of the liftingcam follower 1101 and the lifting cam groove 1032. Even when theconstitution is adopted where the penetration cam frame 1100 is lifted,that is, is moved in the optical axis direction relative to the seconddrive frame 1030 by making the penetration cam frame 1100 and the seconddrive frame 1030 engage with each other by a plurality of cam mechanismshaving the substantially same trajectory, the engagement strength isminimally lowered. In three kinds of cam mechanisms adopted in thisembodiment, one kind of cam follower and two kinds of cam grooves arearranged on a penetration cam frame 1100 side, and one kind of camgroove and two kinds of cam followers are arranged on a second driveframe 1030 side. However, the present invention is not limited to sucharrangement. The arrangement may be adopted where three kinds of camfollowers are arranged on the same frame side, and three kinds of camgrooves are arranged on a counterpart frame side.

Bayonet ribs 1022 and bayonet ribs 1023 of the first drive frame 1020engage with bayonet grooves 1104 and bayonet grooves 1105 of thepenetration cam frame 1100 respectively.

With this constitution, since the lifting cam follower 1101 and thelifting cam groove 1032 engage with each other, when the second driveframe 1030 is rotated with respect to the penetration cam frame 1100 forshifting the barrel to a telescopic state from a collapsed state, thepenetration cam frame 1100 is lifted, that is, is moved toward a frontside in the optical axis direction relative to the second drive frame1030. Further, the bayonet ribs 1022 and the bayonet ribs 1023 engagewith the bayonet grooves 1104 and the bayonet grooves 1105 of thepenetration cam frame 1100 respectively and hence, the first drive frame1020 is lifted, that is, is moved toward a front side in the opticalaxis direction relative to the second drive frame 1030 together with thepenetration cam frame 1100.

Since the rotation restricting portion 1021 of the first drive frame1020 and the rotation restricting portion 1031 of the second drive frame1030 engage with each other (are brought into contact with each other),when the second drive frame 1030 is rotated, the first drive frame 1020is rotated along with the rotation of the second drive frame 1030. Whenthe bayonet ribs 1022 and the bayonet ribs 1023 are moved along thebayonet grooves 1104 and the bayonet grooves 1105, the first drive frame1020 is rotated with respect to the penetration cam frame 1100. In suchan operation, the relative movement of the first drive frame 1020 in theoptical axis direction with respect to the penetration cam frame 1100 isrestricted. At this state of operation, as shown in FIGS. 25, 26, thesecond drive frame 1030 is moved so as to approach the first drive frame1020 in a collapsed state, and is moved so as to be away from the firstdrive frame 1020 in a telescopic state.

(Effects and the Like)

The lens barrel of the present disclosure includes: the first frame (thepenetration cam frame 1100); the second frame (the first drive frame1020) which is rotatably supported relative to the first frame (thepenetration cam frame 1100) about the optical axis, and has the firstgroove (the rotation restricting groove 1024); the third frame (thesecond drive frame 1030) which is rotatably supported relative to thefirst frame (the penetration cam frame 1100) about the optical axis, andhas the second groove (the rotation restricting groove 1035); the fourthframe (the double-sided cam frame 1310) which has a first follower (arotation restricting projection 1311) which is engageable with a firstgroove (a rotation restricting groove 1024) and a second groove (arotation restricting groove 1035) and is movable with respect to thesecond frame (the first drive frame 1020) and the third frame (thesecond drive frame 1030) in the optical axis direction; and the movingmechanism (the cam mechanism constituted of the lifting cam follower1101 and the lifting cam groove 1032) which moves the third frame (thesecond drive frame 1030) relative to the second frame (the first driveframe 1020) in the optical axis direction when the third frame (thesecond drive frame 1030) is rotated relative to the first frame, whereinthe first follower (the rotation restricting projection 1311) is formedin a shape by which the first follower (the rotation restrictingprojection 1311) can continuously transit between the first groove (therotation restricting groove 1024) and the second groove (the rotationrestricting groove 1035).

With this constitution, the second frame (the first drive frame 1020)and the third frame (the second drive frame 1030) arranged on the singlefirst frame (the penetration cam frame 1100) can be moved in a separatedmanner and hence, a moving amount of the fourth frame (the double-sidedcam frame 1310) can be increased. Further, the miniaturization (thereduction of thickness) of the lens barrel in the optical axis directioncan be realized while increasing the moving amount of the fourth frame(the double-sided cam frame 1310).

In the lens barrel of the present disclosure, the moving mechanism isconstituted of the cam mechanism (the lifting cam follower 1101 and thelifting cam groove 1032).

With this constitution, the third frame (the second drive frame 1030)can be moved relative to the second frame (the first drive frame 1020)in the optical axis direction with the simple structure constituted ofthe cam mechanism (the lifting cam follower 1101 and the lifting camgroove 1032).

In the lens barrel of the present disclosure, the cam mechanism isconstituted of the cam follower (the lifting cam follower 1101) of thefirst frame (the penetration cam frame 1100) and the cam groove (thelifting cam groove 1032) of the third frame (the second drive frame1030).

With this constitution, the cam mechanism can be formed with the simplestructure.

In the lens barrel of the present disclosure, the second frame (thefirst drive frame 1020) has the first rotation restricting portion (therotation restricting portion 1021), and the third frame (the seconddrive frame 1030) has the second rotation restricting portion (therotation restricting portion 1031) which engages with the first rotationrestricting portion (the rotation restricting portion 1021).

With this constitution, it is possible to make the second frame (thefirst drive frame 1020) and the third frame (the second drive frame1030) move relative to each other in the optical axis direction whilerestricting the relative rotation between the second frame (the firstdrive frame 1020) and the third frame (the second drive frame 1030).

The lens barrel of the present disclosure further includes the drivemotor (the zooming motor unit 910) where the drive gear (the drive gear910 a) is joined to the drive shaft, the driven gear portion (the drivengear portion 1037) which meshes with the drive gear of the drive motor(the zooming motor unit 910) and rotates the third frame (the seconddrive frame 1030) about the optical axis is formed on a rear end side ofan outer peripheral surface of the third frame (the second drive frame1030) in the circumferential direction, and the driven gear portion (thedriven gear portion 1037) is formed so as to make a predetermined anglewith respect to the circumferential direction such that one end side ofthe driven gear portion (the driven gear portion 1037) in thecircumferential direction projects toward a rear side from a rear end ofthe third frame (the second drive frame 1030).

With this constitution, the rear end flange portion 1100 a of thepenetration cam frame 1100 can be formed largely and also in a widerange. Accordingly, the penetration cam frame 1100 can ensure thestrength and hence, the penetration cam frame 1100 is minimally brokenby an external force such as falling. Further, the total length of thelens barrel in a collapsed state can be further shortened.

The lens barrel of the present disclosure includes: the first frame (thepenetration cam frame 1100); the second frame (the first drive frame1020) which is supported rotatably relative to the first frame (thepenetration cam frame 1100) about the optical axis; the moving member(the fifth group drive arm 520) which is movably supported in theoptical axis direction on the second frame (the first drive frame 1020);the third frame (the fifth group lens frame 510) which is arranged so asto face the moving member (the fifth group drive arm 520) in an opposedmanner in the optical axis direction, and is movably supported in theoptical axis direction; and the biasing means (the biasing spring 603)which biases the moving member (the fifth group drive arm 520) and thethird frame (the fifth group lens frame 510) in the directions that themoving member (the fifth group drive arm 520) and the third frame (thefifth group lens frame 510) are brought into contact with each other.The lens barrel of the present disclosure also includes the movingmechanism (the cam follower 523, the drive cam groove 1036) which movesthe moving member (the fifth group drive arm 520) in the optical axisdirection when the second frame (the first drive frame 1020) is rotatedrelative to the first frame (the penetration cam frame 1100).

With this constitution, it is possible to move the third frame (thefifth group lens frame 510) in the optical axis direction by way of themoving member (the fifth group drive arm 520) corresponding to therelative rotation between the first frame (the penetration cam frame1100) and the second frame (the first drive frame 1020).

This embodiment also discloses the following constitution.

That is, in the lens barrel of the present disclosure, the second frame(the first drive frame 1020) further includes the first rotationrestricting portion (the rotation restricting portion 1021), the thirdframe (the second drive frame 1030) further includes the second rotationrestricting portion (the rotation restricting portion 1031), and thesecond frame (the first drive frame 1020) and the third frame (thesecond drive frame 1030) engage with the first rotation restrictingportion (the rotation restricting portion 1021) and the second rotationrestricting portion (the rotation restricting portion 1031) when therelative positions in the optical axis direction of the second frame(the first drive frame 1020) and the third frame (the second drive frame1030) in the optical axis direction are changed thus restricting therotations.

With this constitution, it is unnecessary to apply the restriction ofrotation to the second frame (the first drive frame 1020) and the thirdframe (the second drive frame 1030) respectively from other frames.

In the lens barrel of the present disclosure, the second frame (thefirst drive frame 1020) and the third frame (the second drive frame1030) are arranged along the optical axis direction, and opposedlyfacing outer diameters of the second frame (the first drive frame 1020)and the third frame (the second drive frame 1030) are set to thesubstantially same diameter, and opposedly facing inner diameters of thesecond frame (the first drive frame 1020) and the third frame (thesecond drive frame 1030) are set to the substantially same diameter. Thefirst rotation restricting portion (the rotation restricting portion1021) and the second rotation restricting portion (the rotationrestricting portion 1031) are arranged between the outer diameter andthe inner diameter which are substantially the same diameter between thesecond frame (the first drive frame 1020) and the third frame (thesecond drive frame 1030). The radial direction position of the firstrotation restricting portion (the rotation restricting portion 1021) isset substantially equal to the radial direction position of the firstgroove (the rotation restricting groove 1024), and the radial directionposition of the second rotation restricting portion (the rotationrestricting portion 1031) is set substantially equal to the radialdirection position of the second groove (the rotation restricting groove1035). In other words, the radial direction position of the firstrotation restricting portion (the rotation restricting portion 1021) hasat least a portion thereof overlapping with the radial directionposition of the first groove (the rotation restricting groove 1024), andthe radial direction position of the second rotation restricting portion(the rotation restricting portion 1031) has at least a portion thereofoverlapping with the radial direction position of the second groove (therotation restricting groove 1035).

With this constitution, a moving amount of the fourth frame (thedouble-sided cam frame 1310) can be increased without increasing thesize in the radial direction.

In the lens barrel of the present disclosure, the fifth frame (theornamental ring 1010) is fixed to the outer peripheral portion of thesecond frame (the first drive frame 1020) and hence, the fifth frame(the ornamental ring 1010) and the second frame (the first drive frame1020) are integrally joined to each other. It is sufficient that thelength of the fifth frame (the ornamental ring 1010) in the optical axisdirection is the length with which a gap formed when the positions ofthe second frame (the first drive frame 1020) and the third frame (thesecond drive frame 1030) in the optical axis direction are changed canbe concealed, that is, the length which is longer than amounts ofchanges of the positions of the respective frames in the optical axisdirection. In the present disclosure, the length of the fifth frame (theornamental ring 1010) is set to the length with which the fifth frame(the ornamental ring 1010) covers the second frame (the first driveframe 1020), a gap formed between the second frame (the first driveframe 1020) and the third frame (the second drive frame 1030) isconcealed, and the fifth frame (the ornamental ring 1010) covers aportion of the third frame (the second drive frame 1030) observed inexternal appearance. In this case, the fifth frame (the ornamental ring1010) and the second frame (the first drive frame 1020) are fixed toeach other and hence, the fifth frame (the ornamental ring 1010) and thesecond frame (the first drive frame 1020) may be brought into closecontact to each other. However, the fifth frame (the ornamental ring1010) changes the position thereof in the optical axis direction withrespect to the third frame (the second drive frame 1030), that is, thefifth frame (the ornamental ring 1010) and the third frame (the seconddrive frame 1030) move relative to each other and hence, it is necessaryto make the fifth frame (the ornamental ring 1010) and the third frame(the second drive frame 1030) face each other with a gap formedtherebetween in the radial direction. It is preferable to set this gapin the radial direction to approximately 0.01 mm to 0.5 mm.

With this constitution, even when a gap, that is, a separated portion isformed due to a change in positions of the second frame (the first driveframe 1020) and the third frame (the second drive frame 1030) in theoptical axis direction, such a gap can be concealed. Accordingly, theaesthetic appearance of the lens barrel can be ensured, the intrusion ofharmful light can be suppressed, and the intrusion of dust or a foreignsubstance can be suppressed.

The lens barrel of the present disclosure includes the first cammechanism constituted of the first frame (the penetration cam frame1100) and the third frame (the second drive frame 1030), and therelative position of the first frame (the penetration cam frame 1100)and the third frame (the second drive frame 1030) in the optical axisdirection can be changed by the first cam mechanism. The first cammechanism is formed by the engagement between the lifting cam follower1101 of the first frame (the penetration cam frame 1100) and the liftingcam groove 1032 of the third frame (the second drive frame 1030). Thelens barrel includes the second cam mechanism which is constituted ofthe first frame (the penetration cam frame 1100) and the second frame(the first drive frame 1020), and the first frame (the penetration camframe 1100) and the second frame (the first drive frame 1020) engagewith each other in a relatively rotatable manner while not changing therelative position in the optical axis direction therebetween by thesecond cam mechanism. The second cam mechanism is constituted of theengagement between the bayonet grooves 1104 and the bayonet grooves 1105of the first frame (the penetration cam frame 1100) and the bayonet ribs1022 and the bayonet ribs 1023 of the second frame (the first driveframe 1020).

With this constitution, the positions of the second frame (the firstdrive frame 1020) and the third frame (the second drive frame 1030) inthe optical axis direction can be changed without increasing the numberof parts or without increasing the size in the radial direction.

In the lens barrel of the present disclosure, the first radial directionrestricting portion (the radial direction restricting portion 1112) andthe second radial direction restricting portion (the radial directionrestricting portion 1113) are formed on the outer periphery of the firstframe (the penetration cam frame 1100), and the third radial directionrestricting portion (the radial direction restricting portion 1025) isformed on the inner periphery of the second frame (the first drive frame1020), and the fourth radial direction restricting portion (the radialdirection restricting portion 1039) is formed on the inner periphery ofthe third frame (the second drive frame 1030). Due to the engagementbetween the first radial direction restricting portion (the radialdirection restricting portion 1112) and the third radial directionrestricting portion (the radial direction restricting portion 1025), thesecond frame (the first drive frame 1020) is restricted in the radialdirection with respect to the first frame (the penetration cam frame1100). Due to the engagement between the second radial directionrestricting portion (the radial direction restricting portion 1113) andthe fourth radial direction restricting portion (the radial directionrestricting portion 1039), the third frame (the second drive frame 1030)is restricted in the radial direction with respect to the first frame(the penetration cam frame 1100).

With this constitution, it is unnecessary to provide the radialdirection restriction between the second frame (the first drive frame1020) and the third frame (the second drive frame 1030) and hence, thelens barrel can be formed without increasing the size in the radialdirection.

In the lens barrel of the present disclosure, the first frame (thepenetration cam frame 1100) has the third groove (the penetration camgroove 1106), the fourth frame (the double-sided cam frame 1310) has thesecond follower (the cam follower 1312) which engages with the thirdgroove (the penetration cam groove 1106), and the third cam mechanism isconstituted of the third groove (the penetration cam groove 1106) andthe second follower (the cam follower 1312). When the second frame (thefirst drive frame 1020) is rotated relative to the first frame (thepenetration cam frame 1100), the second follower (the cam follower 1312)is moved along the third groove (the penetration cam groove 1106) andhence, the fourth frame (the double-sided cam frame 1310) is moved inthe optical axis direction while rotating with respect to the firstframe (the penetration cam frame 1100).

Due to such an operation, the fourth frame (the double-sided cam frame1310) can be moved without increasing the number of parts or withoutincreasing the size in the radial direction.

The lens barrel of the present disclosure further includes the sixthframe (the fixed frame 900) which is supported rotatably relative to thethird frame (the second drive frame 1030). The third frame (the seconddrive frame 1030) is moved with the relative rotation between the thirdframe (the second drive frame 1030) and the sixth frame (the fixed frame900) by the fourth cam mechanism constituted of the sixth frame (thefixed frame 900) and the third frame (the second drive frame 1030). Thelens barrel further includes the seventh frame (the first group unit100) which is rotatably supported relative to the fourth frame (thedouble-sided cam frame 1310), and the seventh frame (the first groupunit 100) and the fourth frame (the double-sided cam frame 1310) aremoved in the optical axis direction while being rotatable relative toeach other by the fifth cam mechanism constituted of the fourth frame(the double-sided cam frame 1310) and the seventh frame (the first groupunit 100). Assuming a moving amount of the third frame (the second driveframe 1030) in the optical axis direction with respect to the sixthframe (fixed frame 900) by the fourth cam mechanism as α, a movingamount of the first frame (the penetration cam frame 1100) in theoptical axis direction with respect to the third frame (the second driveframe 1030) by the first cam mechanism as β, a moving amount of thefourth frame (the double-sided cam frame 1310) in the optical axisdirection with respect to the first frame (the penetration cam frame1100) by the third cam mechanism as γ, and a moving amount of theseventh frame (the first group unit 100) in the optical axis directionwith respect to the fourth frame (the double-sided cam frame 1310) bythe fifth cam mechanism as δ, a moving amount of the seventh frame (thefirst group unit 100) with respect to the sixth frame (the fixed frame900) is expressed as α+β+γ+δ.

In this manner, the lens barrel of the present disclosure can acquire anextending amount comparable to an extending amount of a four-stagecollapsible barrel, that is, an extending amount of α+β+γ+δ whileexhibiting the same external appearance as a three-stage collapsiblebarrel, that is, having the substantially same outer diameter as athree-stage collapsible barrel. The lens barrel of the presentdisclosure can extend the moving amount by β compared to theconventional three-stage collapsible barrel. In the present disclosure,the first groove and the second groove are formed as the rotationrestricting groove and the third groove is formed as the cam groove.However, the grooves may be used in an opposite manner. That is, thesame advantageous effect can be acquired by using the first groove andthe second groove as the cam grooves and the third groove as therotation restricting groove. In the present disclosure, in the secondcam mechanism, the first frame (the penetration cam frame 1100) and thesecond frame (the first drive frame 1020) are configured such that therelative position in the optical direction is not changed. However, thefirst frame (the penetration cam frame 1100) and the second frame (thefirst drive frame 1020) are configured such that the relative positionin the optical direction is changed. The same effects can be obtained bysuch a constitution. In the present disclosure, the fifth frame (theornamental ring 1010) is formed as a member separate from the secondframe (the first drive frame 1020), the fifth frame (the ornamental ring1010) and the second frame (the first drive frame 1020) may be formed asone integral part. Such a part can also acquire the same advantageouseffect. Although the fifth frame (the ornamental ring 1010) is fixed tothe second frame (the first drive frame 1020) in the present disclosure,the fifth frame (the ornamental ring 1010) may be fixed to the thirdframe (the second drive frame 1030). In this case, the second frame (thefirst drive frame 1020) and the fifth frame (the ornamental ring 1010)may be arranged to face each other with a gap formed therebetween in theradial direction. Such a constitution can also acquire the sameadvantageous effect. The fifth frame (the ornamental ring 1010) and thethird frame (the second drive frame 1030) may be formed as one integralpart. Such a part can also acquire the same advantageous effect.

[3.5. (Double-Sided Cam Frame)]

FIG. 16 is a perspective view of the double-sided cam frame 1310.

FIG. 17 is a constitutional view of the double-sided cam frame 1310.FIG. 17A is a front view of the double-sided cam frame 1310, FIG. 17B isa view of the double-sided cam frame 1310 as viewed in the directionindicated by D in FIG. 17A, and FIG. 17C is a view of the double-sidedcam frame 1310 as viewed in the direction indicated by E in FIG. 17A.

As shown in FIGS. 16 and 17, the double-sided cam frame 1310 is formedinto a circular cylindrical shape. The double-sided cam frame 1310 isformed by injection molding using a resin. The double-sided cam frame1310 is arranged on an inner peripheral side of the penetration camframe 1100. A rotation restricting projection 1311 and a cam follower1312 are formed on the double-sided cam frame 1310. The cam follower1312 is formed in a radially projecting manner from a rear end portionof the double-sided cam frame 1310. The cam follower 1312 engages withthe penetration cam groove 1106 of the penetration cam frame 1100. Thecam follower 1312 has a shape formed by arranging two frustoconicalbases in the circumferential direction and by connecting bothfrustoconical bases. By forming the cam follower 1312 into such a shape,compared to a cam follower having the structure where only onefrustoconical base is arranged, the cam follower 1312 can increase across-sectional area of the cam follower in the circumferentialdirection. Accordingly, even when an external force is applied to thelens barrel due to falling or the like, the lens barrel is minimallybroken.

The rotation restricting projection 1311 has a form configured such thatthe rotation restricting projection 1311 projects in the radialdirection from a distal end of the cam follower 1312, and a distal endof the rotation restricting projection 1311 extends toward a front sidein the optical axis direction.

As shown in FIG. 19, the rotation restricting projection 1311 engageswith the rotation restricting groove 1024 of the first drive frame 1020and the rotation restricting groove 1035 of the second drive frame 1030(see FIG. 13). As shown in FIG. 19, in a collapsed state, a rear endportion of the rotation restricting groove 1035 of the second driveframe 1030 is disposed away from the rear end flange portion 1100 a ofthe penetration cam frame 1100. With this constitution, when thepenetration cam frame 1100 is lifted toward a front side in the opticalaxis direction, that is, when the penetration cam frame 1100 is movedtoward a front side in the optical axis direction along with theshifting of the lens barrel to a telescopic state from a collapsed stateas described previously, it is possible to ensure a space for preventingthe interference of the rear end flange portion 1100 a of thepenetration cam frame 1100 with the rear end portion of the second driveframe 1030. The rotation restricting projection 1311 is, in a collapsedstate shown in FIG. 19, formed in an extending manner toward a frontside in the optical axis direction such that the rotation restrictingprojection 1311 reaches a rear end portion of the rotation restrictinggroove 1035 disposed away from the rear end flange portion 1100 a of thepenetration cam frame 1100. As shown in FIG. 20, when the lens barrel isin a telescopic state, the front end portion of the extending portion ofthe rotation restricting projection 1311 is made to approach and facethe front side flange portion of the ornamental ring 1010 in an opposedmanner without interposing the first drive frame 1020 between the frontend portion of the extending portion of the rotation restrictingprojection 1311 and the front flange portion of the ornamental ring 1010in the optical axis direction. In this embodiment, as shown in FIG. 17B,the rotation restricting projection 1311 is disposed at the positionoffset toward a left side from the center of the cam follower 1312 asviewed in the drawing.

FIG. 18 is a developed view of the penetration cam groove 1106.

The penetration cam groove 1106 has a shape which approximatelymonotonously extends toward a right lower position from a left upperposition in the drawing. The penetration cam groove 1106 has a front camsurface 1107 disposed on a front side in the optical axis direction anda rear cam surface 1108 on a rear side in the optical axis direction.

As shown in FIG. 17B, portions of the cam follower 1312 which slide inthe penetration cam groove 1106 are only a conical surface 1313 a and aconical surface 1313 b. The conical surface 1313 a is a portion (a rangeindicated by a solid-line arrow) at a right upper side on a surface ofpaper formed on the first frustoconical base 1312 a on a right side onthe surface of paper out of two frustoconical bases which form the camfollower 1312, wherein such portion faces the front cam surface 1107 ofthe penetration cam groove 1106 shown in FIG. 18 in an opposed manner.The conical surface 1313 b is a portion (a range indicated by asolid-line arrow) at a left lower side on the surface of paper formed onthe second frustoconical base 1312 b on a left side on the surface ofpaper out of two frustoconical bases which form the cam follower 1312,wherein such portion faces the rear cam surface 1108 of the penetrationcam groove 1106 shown in FIG. 18 in an opposed manner. Accordingly, itis sufficient for the cam follower 1312 to ensure the size accuracysubstantially equal to the size accuracy of the conical surface 1313 aand the conical surface 1313 b.

In this embodiment, the conical surface 1313 a and the conical surface1313 b are formed on portion which slide in the penetration cam groove1106 and predetermined ranges disposed adjacent to the portions. To bemore specific, the conical surface 1313 a is formed within a range of apredetermined angle in the clockwise direction from a front side in theoptical axis direction with respect to the center axis (conical axis) ofthe first frustoconical base 1312 a. The conical surface 1313 b isformed within a range of a predetermined angle in the clockwisedirection from a rear side in the optical axis direction with respect tothe center axis (conical axis) of the second frustoconical base 1312 b.

Further, in this embodiment, to ensure the dimensional accuracy of thecam follower 1312, as a mold part for forming the double-sided cam frame1310 by injection molding, a mold part which can form a single mold partwithin an accuracy ensured range 1314 (a range indicated by abroken-line arrow) is used. The accuracy ensured range 1314 is a rangefrom the position which is routed around the conical surface 1313 a ofthe first frustconical base 1312 a by a predetermined angle in theclockwise direction from a front side as viewed from an outer side inthe radial direction of a conical axis to the position which is routedaround the conical surface 1313 b of the second frustconical base 1312 bby a predetermined angle in the counterclockwise direction from a rearside as viewed from an outer side in the radial direction of a conicalaxis. Due to such processing, the accuracy ensured range 1314 (the rangeindicated by a broken-line arrow) can be formed by a single mold partand hence, the accuracy of the part can be made stable. This single moldpart can be moved (slid) in the radial direction at the time of molding.As a result, when the rotation restricting projection 1311 and theaccuracy ensured range 1314 overlap with each other as viewed from theradial direction, these parts cannot be formed by a single mold part.Accordingly, in forming the accuracy ensured range 1314 by the singlemold part, it is necessary to adopt the constitution where the rotationrestricting projection 1311 and the accuracy ensured range 1314 do notoverlap with each other as viewed in the radial direction.

It is necessary to form the rotation restricting projection 1311 suchthat the rotation restricting projection 1311 has a side surface 1315and a side surface 1316, the side surface 1315 and the conical surface1313 a do not overlap with each other as viewed in the radial direction,and the side surface 1316 and the conical surface 1313 b do not overlapwith each other as viewed in the radial direction. The side surface 1315and the side surface 1316 of the rotation restricting projection 1311are formed so as to extend to a front side in the optical axis directionfrom the cam follower 1312. Accordingly, the side surface 1315 and theside surface 1316 do not extend toward a rear side from the conical axisof the cam follower 1312 in the optical axis direction and hence, theside surface 1315 and the side surface 1316 do not overlap with the camfollower 1312 as viewed in the radial direction. To widen a width of therotation restricting projection 1311, that is, a distance “h” betweenthe side surface 1315 and the side surface 1316 while ensuring theaccuracy ensured range 1314 (a range from the position which is routedaround the conical surface 1313 a of the first frustconical base 1312 aby a predetermined angle in the clockwise direction from a front side asviewed from an outer side in the radial direction of a conical axis tothe position which is routed around the conical surface 1313 b of thesecond frustconical base 1312 b by a predetermined angle in thecounterclockwise direction from a rear side as viewed from an outer sidein the radial direction of a conical axis), it is sufficient to move theside surface 1316 toward a left side on a surface of paper, that is, inthe direction away from an intermediate point between the firstfrustoconical base 1312 a and the second frustconical base 1312 b. Inthe second frustconical base 1312 b, the conical surface 1313 b whichrequires accuracy exists only on a rear side in the optical axisdirection with respect to the conical axis of the cam follower 1312 andhence, even when the side surface 1316 overlaps with the portion more ona front side in the optical axis direction than the conical axis of thesecond frustconical base 1312 b, the accuracy of the conical surface1313 b can be ensured. In the first frustconical base 1312 a, theconical surface 1313 a which requires accuracy exists more on a frontside in the optical axis direction than the conical axis of the camfollower 1312 and hence, when the side surface 1315 overlaps with aportion of the first frustconical base 1312 a more on a front side inthe optical axis direction than the conical axis of the cam follower1312, the accuracy ensured range 1314 cannot be formed by a single moldpart and hence, the accuracy of the conical surface 1313 a cannot beensured. Accordingly, it is necessary to form the side surface 1315 moreon a second frustoconical base 1312 b side in the circumferentialdirection than the conical axis of the first frustconical base 1312 a.To satisfy this requirement, the rotation restricting projection 1311 isformed in a shape where the rotation restricting projection 1311 isoffset toward a left side on a surface of paper from the center of thecam follower 1312, that is, an intermediate point between the firstfrustconical base 1312 a and the second frustconical base 1312 b. Byforming the side surface 1315 in this manner, the size of the width “h”can be ensured and hence, the strength of the rotation restrictingprojection 1311 can be ensured. Further, both the accuracy of the camfollower 1312 and the strength of the rotation restricting projection1311 can be acquired.

As described above, the double-sided cam frame 1310 includes: the camfollower 1312 having a shape where the first frustconical base 1312 aand the second frustconical base 1312 b are arranged in thecircumferential direction and are joined to each other; and the rotationrestricting projection 1311 which is formed such that the rotationrestricting projection 1311 projects in the radial direction from thecam follower 1312 and, further, extends toward a front side in theoptical axis direction. The rotation restricting projection 1311 has theside surface 1315 and the side surface 1316 which differ from each otherin the circumferential distance from an intermediate point between thefirst frustconical base 1312 a and the second frustconical base 1312 b.The side surface 1315 is disposed at the approximately same position asthe conical axis of the first frustconical base 1312 a or on a sidecloser to the intermediate point (the intermediate position between thefirst frustconical base 1312 a and the second frustconical base 1312 b)than the conical axis of the first frustconical base 1312 a in thecircumferential direction. The side surface 1316 is disposed at theapproximately same position as the conical axis of the secondfrustconical base 1312 b or on a side remoter from the intermediatepoint than the conical axis of the second frustconical base 1312 b inthe circumferential direction.

[3.6. Engaging State of Drive Frame Unit, Penetration Cam Frame andDouble-Side Cam Frame]

FIGS. 19A and 19B are views showing the relationship in a collapsedstate among the drive frame unit 1000, the penetration cam frame 1100and the double-sided cam frame 1310. FIG. 19A is a view of the driveframe unit 1000 as viewed from the optical axis direction, and FIG. 19Bis a cross-sectional view taken along a line C-C in FIG. 19A.

FIGS. 20A and 20B are views showing the relationship in a telescopicstate among the drive frame unit 1000, the penetration cam frame 1100and the double-sided cam frame 1310. FIG. 20A is a view of the driveframe unit 1000 as viewed from the optical axis direction, and FIG. 20Bis a cross-sectional view taken along a line D-D in FIG. 20A.

When the second drive frame 1030 is rotated with respect to thepenetration cam frame 1100 for shifting the lens barrel to a telescopicstate from a collapsed state, the lifting cam follower 1101 engages withthe lifting cam groove 1032. Due to such engagement, the penetration camframe 1100 is lifted, that is, is moved toward a front side in theoptical axis direction relative to the second drive frame 1030 andhence, the bayonet ribs 1022 and the bayonet ribs 1023 engage with thebayonet grooves 1104 and the bayonet grooves 1105 of the penetration camframe 1100 respectively. Accordingly, the first drive frame 1020 islifted, that is, is moved toward a front side in the optical axisdirection relative to the second drive frame 1030 together with thepenetration cam frame 1100.

When the second drive frame 1030 is rotated with respect to thepenetration cam frame 1100 from a collapsed state, the double-sided camframe 1310 is moved toward a front side in the optical axis directionwhile being rotated with respect to the penetration cam frame 1100 bythe cam mechanism. The cam mechanism is constituted of: the penetrationcam groove 1106 of the penetration cam frame 1100; the cam follower 1312which engages with the penetration cam groove 1106; the rotationrestricting groove 1035 of the second drive frame 1030; and the rotationrestricting projection 1311 which engages with the rotation restrictinggroove 1035.

In an initial state when the lens barrel is shifted to a telescopicstate from a collapsed state, the first drive frame 1020 and the seconddrive frame 1030 are being held in a state where the first drive frame1020 and the second drive frame 1030 are close to each other in theoptical axis direction and hence, a distance D1 in the optical axisdirection between the first drive frame 1020 and the second drive frame1030 is small. In this state, two grooves, that is, the rotationrestricting groove 1024 of the first drive frame 1020 and the rotationrestricting groove 1035 of the second drive frame 1030 are close to eachother and are formed continuously as if two grooves form one groove.

When the double-sided cam frame 1310 is moved toward a front side in theoptical axis direction while being rotated with respect to thepenetration cam frame 1100, the cam follower 1312 is moved in thepenetration cam groove 1106. At this stage of the operation, therotation restricting projection 1311 is moved in the rotationrestricting groove 1035 of the second drive frame 1030 and, thereafter,transits to the rotation restricting groove 1024 of the first driveframe 1020 disposed continuously with the rotation restricting groove1035, and is moved in the rotation restricting groove 1024.

When the second drive frame 1030 is rotated with respect to thepenetration cam frame 1100 so as to shift the lens barrel to atelescopic state from a collapsed state, the rotation restrictingprojection 1311 transits to the rotation restricting groove 1024 of thefirst drive frame 1020 from the rotation restricting groove 1035 of thesecond drive frame 1030 and, thereafter, the lifting cam follower 1101engages with the lift portion of the lifting cam groove 1032, that is,the optical-axis-direction moved portion of the lifting cam groove 1032.Accordingly, the penetration cam frame 1100 is lifted, that is, is movedtoward a front side in the optical axis direction relative to the seconddrive frame 1030. Then, the bayonet ribs 1022 and the bayonet ribs 1023engage with the bayonet grooves 1104 and the bayonet grooves 1105 of thepenetration cam frame 1100 respectively. Accordingly, the first driveframe 1020 is lifted, that is, moved toward a front side in the opticalaxis direction relative to the second drive frame 1030 together with thepenetration cam frame 1100. As a result, the position of the seconddrive frame 1030 and the position of the first drive frame 1020 areseparated from each other in the optical axis direction so that adistance D2 in the optical axis direction between the first drive frame1020 and the second drive frame 1030 is increased. (D2>D1)

In this embodiment, the rotation restricting projection 1311 transits tothe rotation restricting groove 1024 from the rotation restrictinggroove 1035 and, thereafter, the second drive frame 1030 and the firstdrive frame 1020 are separated from each other in the optical axisdirection. However, the present invention is not limited to such amanner of operation. The second drive frame 1030 and the first driveframe 1020 may be separated from each other in the optical axisdirection before the rotation restricting projection 1311 transits tothe rotation restricting groove 1024 from the rotation restrictinggroove 1035 or in the midst of the transition. In this case, it issufficient that a length of the rotation restricting projection 1311 inthe optical axis direction is equal to or longer than the predeterminedlength D2. That is, it is sufficient that the length D2 of the rotationrestricting projection 1311 is larger than a distance formed between thesecond drive frame 1030 and the first drive frame 1020 when the rotationrestricting projection 1311 transits to the rotation restricting groove1024 from the rotation restricting groove 1035.

The rotation restricting groove 1024 of the first drive frame 1020 andthe rotation restricting groove 1035 of the second drive frame 1030engage with the rotation restricting portion 1021 and the rotationrestricting portion 1031 respectively and hence, even when thepositional relationship in the optical axis direction changes, there isno possibility that the positional relationship in the circumferentialdirection, that is, in the rotation angle direction changes.

As shown in FIG. 19B, the rotation restricting projection 1311 ispositioned in the rotation restricting groove 1035 of the second driveframe 1030. When the lens barrel is moved to a telescopic state shown inFIG. 20 from a collapsed state shown in FIG. 19, the rotationrestricting projection 1311 is moved in a transiting manner to therotation restricting groove 1024 of the first drive frame 1020 from therotation restricting groove 1035 of the second drive frame 1030. Asdescribed previously, the rotation restricting projection 1311 is formedin a shape extending in the optical axis direction and having the lengthequal to or more than the predetermined length in the optical axisdirection and hence, the rotation restricting projection 1311 can surelytransit to the rotation restricting groove 1024 of the first drive frame1020 from the rotation restricting groove 1035 of the second drive frame1030.

As described previously, when the lens barrel is moved to a telescopicstate shown in FIG. 20 from a collapsed state shown in FIG. 19, thesecond drive frame 1030 and the first drive frame 1020 are separatedfrom each other (D1 in FIG. 19 being changed to D2 in FIG. 20). Toconceal such a portion where the second drive frame 1030 and the firstdrive frame 1020 are separated from each other, the ornamental ring 1010is arranged on an outer peripheral side of the second drive frame 1030and an outer peripheral side of the first drive frame 1020.

[3.7. Description of Driving of Fifth Group Unit]

Driving of the fifth group unit 500 is described with reference to FIGS.21 to 23 and FIG. 27.

As shown in FIG. 21, the fifth group lens frame 510 includes: a guideportion 511; a guide portion 512; a contact portion 513; a contactportion 514; and an engaging portion 515. The guide portion 511 engageswith a fifth group guide shaft 601 in such a manner that the guideportion 511 allows the movement of the fifth group lens frame 510 in theoptical axis direction while restricting the position of the fifth grouplens frame 510 in a plane orthogonal to the optical axis and theinclination of the fifth group lens frame 510 in the plane orthogonal tothe optical axis. The guide portion 512 restricts the position of thefifth group lens frame 510 in the plane orthogonal to the optical axistogether with the guide portion 511. A biasing spring 603 which biasesthe fifth group lens frame 510 toward a front side in the optical axisdirection is brought into contact with the contact portion 513. Thecontact portion 514 is brought into contact with a contact portion 526of the fifth group drive arm 520. With this constitution, the positionof the contact portion 514 in the optical axis direction changescorresponding to the position of the fifth group drive arm 520 in theoptical axis direction. The engaging portion 515 engages with theposition restricting portion 604 of the master flange unit 600 so as tohold the fifth group lens frame 510 such that the fifth group lens frame510 is not removed from the master flange unit 600. The fifth group lensframe 510 is held by the master flange unit 600 by way of the fifthgroup guide shaft 601 and the fifth group guide shaft 602. The fifthgroup lens frame 510 is biased toward a front side by the biasing spring603 mounted on the fifth group guide shaft 601.

The fifth group guide shaft 601 and the fifth group guide shaft 602 arefixed to the master flange unit 600 approximately parallel to theoptical axis. The master flange unit 600 includes: a shaft fixingportion 606; the position restricting portion 604; and a contact portion605. The shaft fixing portion 606 fixes the fifth group guide shaft 601to the master flange unit 600. The position restricting portion 604engages with the engaging portion 515 of the fifth group lens frame 510thus restricting the movement of the fifth group lens frame 510 in theoptical axis direction. The contact portion 605 is brought into contactwith the biasing spring 603. In a state taken in the course ofassembling the lens barrel 2000, the fixed frame 900 is not joined tothe master flange unit 600, and the fifth group drive arm 520 is notpresent on a front side of the fifth group lens frame 510. At this stageof operation, the fifth group lens frame 510 is biased toward a frontside by the biasing spring 603 and hence, the engaging portion 515 ofthe fifth group lens frame 510 and the position restricting portion 604of the master flange unit 600 engage with each other. Accordingly, thereis no possibility that the fifth group lens frame 510 is removed fromthe master flange unit 600.

The fifth group drive arm 520 has a shape (an arc shape) whichcorresponds to an arc which constitutes a portion of a circular cylinderabout the optical axis. As shown in FIG. 17, FIGS. 22, 23 and FIG. 27,the fifth group drive arm 520 includes: the rotation restricting portion521; a radial-direction restricting portion 522; three cam followers523; a radial-direction restricting portion 524; the rotationaldirection restricting portion 525; and a contact portion 526. Therotation restricting portion 521 engages with a guide groove 1111 formedon the penetration cam frame 1100 thus restricting the rotation of thefifth group drive arm 520 with respect to the optical axis. Theradial-direction restricting portion 522 engages with a restrictingportion 1110 formed on the penetration cam frame 1100 thus restrictingthe movement of the fifth group drive arm 520 in the radial direction.The cam follower 523 engages with three drive cam grooves 1036 formed onan inner peripheral surface of the second drive frame 1030 (see FIG. 24)thus restricting the movement of the fifth group drive arm 520 in theoptical axis direction. The radial-direction restricting portion 524engages with a restricting portion 901 formed on the fixed frame 900thus restricting the movement of the fifth group drive arm 520 in theradial direction. The rotational direction restricting portion 525engages with a restricting portion 902 formed on the fixed frame 900thus restricting the rotation of the fifth group drive arm 520. Thecontact portion 526 is brought into contact with the contact portion 514of the fifth group lens frame 510 thus transmitting the position of thefifth group drive arm 520 in the optical axis direction to the fifthgroup lens frame 510. The fifth group drive arm 520 is arranged outsidein the radial direction of the fourth lens group L4 of the fourth groupunit 400, and connects the drive cam groove 1036 formed on an innerperipheral side of the second drive frame 1030 disposed on a front sidein the optical axis direction and the contact portion 514 of the fifthgroup lens frame 510 to each other. With this constitution, the driveforce of the drive frame unit 1000 can be transmitted to the fifth grouplens frame 510 through the fifth group drive arm 520, the fifth grouplens frame 510 can be driven, even if other movable frame, that is, thefourth group unit 400 is provided between the drive frame unit 1000 andthe fifth group lens frame 510 in the optical axis direction. Morespecifically, the drive force of the zooming motor unit 910 can betransmitted to the fifth group lens frame 510 through the fifth groupdrive arm 520, and the fifth group lens frame 510 can be driven, even ifother movable frame, that is, the fourth group unit 400 which is drivenby the focus motor unit 610 as a second drive source is provided betweenthe drive frame unit 1000 that is driven by the zooming motor unit 910as a first drive source and the fifth group lens frame 510 in theoptical axis direction. Further, the fifth group drive arm 520 has anapproximately arcuate shape or an approximately plate shape not but acylindrical shape and is provided by one in the circumferentialdirection, and then a space for arranging a mechanism for driving thefifth group lens frame 510 can be reduced. Furthermore, the fifth groupdrive arm 520 is provided by one in the circumferential direction.Therefore, the driving cam grooves 1036 and the cam follower 523 can beprovided by one, respectively. That is, the driving cam grooves 1036 andthe cam follower 523 need not to be provided by three (plurality) andthe constitution can be simple.

When the second drive frame 1030 is rotated with respect to thepenetration cam frame 1100, three cam followers 523 of the fifth groupdrive arm 520 are moved along three drive cam grooves 1036 of the seconddrive frame 1030 and hence, the fifth group drive arm 520 is driven inthe optical axis direction (see FIG. 24). When at least two camfollowers 523 out of three cam followers 523 of the fifth group drivearm 520 are simultaneously engaged with the drive cam grooves 1036,compared to the case where only one cam follower 523 is engaged with thedrive cam groove 1036, the rotation of the fifth group drive arm 520with respect to the second drive frame 1030 is minimally generated.Accordingly, the posture of the fifth group drive arm 520 becomes stablethus enhancing the positioning accuracy. Further, in the fifth groupdrive arm 520, the rotation restricting portion 521 engages with theguide groove 1111 formed on the penetration cam frame 1100, and therotational direction restricting portion 525 engages with therestricting portion 902 formed on the fixed frame 900. Accordingly, therotation of the fifth group drive arm 520 is restricted. In the fifthgroup drive arm 520, the radial-direction restricting portion 522engages with the restricting portion 1110 formed on the penetration camframe 1100, and the radial direction restricting portion 524 engageswith the restricting portion 901 formed on the fixed frame 900. Withthis constitution, a change in the position of the fifth group drive arm520 in the radial direction is restricted. As a result, changes in therespective positions of the fifth group drive arm 520 in the opticalaxis direction, the rotational direction and the radial direction can berestricted. Further, changes in the respective positions of the fifthgroup drive arm 520 in both the front side and the rear side in theoptical axis direction. Therefore, the change in the position of thefifth group drive arm 520 can be restricted more accurately.Specifically, changes in the respective positions of the fifth groupdrive arm 520 in the rotational direction and the radial direction canbe restricted, in both the front side and the rear side in the opticalaxis direction. Therefore, changes in the respective positions of thefifth group drive arm 520 in the rotational direction and the radialdirection can be restricted more accurately. When the second drive frame1030 is rotated relative to the penetration cam frame 1100, the fifthgroup drive arm 520 is movable approximately parallel to the opticalaxis while maintaining the posture thereof as it is. Further, in a statewhere the fixed frame 900 into which the second drive frame 1030 and thepenetration cam frame 1100 are assembled is joined to the master flangeunit 600, it is possible to acquire the positional relationship wherethe contact portion 514 of the fifth group lens frame 510 and thecontact portion 526 of the fifth group drive arm 520 can be brought intocontact with each other. In such a position where the contact portion514 and the contact portion 526 can be brought into contact with eachother, a state is taken where the position restricting portion 604 ofthe master flange unit 600 and the engaging portion 515 of the fifthgroup lens frame 510 do not engage with each other, and the fifth grouplens frame 510 is biased toward a front side by the biasing spring 603.Accordingly, the state where the contact portion 514 of the fifth grouplens frame 510 and the contact portion 526 of the fifth group drive arm520 are brought into contact with each other can be maintained. When thesecond drive frame 1030 and the penetration cam frame 1100 are rotatedrelative to each other in such a state, the fifth group drive arm 520 isdriven in the optical axis direction. At this stage of operation, thecontact between the contact portion 514 and the contact portion 526 ismaintained by the biasing spring 603 and hence, the fifth group lensframe 510 is moved in the optical axis direction in an interlockingmanner with the movement of the fifth group drive arm 520. Accordingly,at the time of zooming, the movement of the fifth lens group L5 of thefifth group lens frame 510 can be realized.

In the present disclosure, the fifth group drive arm 520 has an arcshape which is constituted of a portion of the circular cylinder aboutthe optical axis. However, the fifth group drive arm 520 may have aplate-like shape which approximates an arc shape.

In the optical system of the present disclosure, the first lens groupL1, the second lens group L2, the third lens group L3 and the fifth lensgroup L5 are moved in the optical axis direction using the zooming motorunit 910 as a drive source only at the time of zooming, while the fourthlens group L4 is moved in the optical axis direction using the focusmotor unit 610 as a drive source both at the time of performing focusingand at the time of zooming. It is preferable that the movement of thelens group using the zooming motor unit 910 as the drive source isbrought about by the rotation of the drive frame unit 1000 and thedouble-sided cam frame 1310 relative to the fixed frame 900, thepenetration cam frame 1100 and the rotation restricting frame 1200. Thatis, it is preferable that such movement of the lens group is performedby the cam mechanism provided between the respective cylinders. On theother hand, it is preferable that the movement of the lens group usingthe focus motor unit 610 which constitute the drive source is performedby the following mechanism. That is, it is preferable that the mechanismbe supported such that the mechanism is movable in the optical axisdirection with respect to the master flange unit 600, and the lens groupbe driven in the optical axis direction by the focus motor unit 610fixed to the master flange unit 600. This mechanism is assembled inaccordance with the following steps (1) to (3) in general.

-   (1) The mechanism where the zooming motor unit 910 on a fixed frame    900 side, that is, on a front side in the optical axis direction is    used as the drive source is assembled.-   (2) The mechanism where the focus motor unit 610 on a master flange    unit 600 side, that is, on a rear side in the optical axis direction    is used as the drive source is assembled.-   (3) The mechanism on the fixed frame 900 side, that is, on the front    side in the optical axis direction, and the mechanism on the master    flange unit 600 side, that is, on the rear side in the optical axis    direction are joined to each other.

However, in the optical system of the present disclosure, the third lensgroup L3 and the fifth lens group L5 which are moved using the zoomingmotor unit 910 as the drive source are arranged on the front side andthe rear side in the optical axis direction with the fourth lens groupL4 which is moved using the focus motor unit 610 as the drive sourceinterposed therebetween. Accordingly, when the above-mentionedassembling method is used, at the time of joining the mechanism on thefixed frame side and the mechanism on the master flange unit 600 side,the fourth lens group L4 collides with the fifth lens group L5 andhence, assembling cannot be performed. In other words, when there areprovided at least three movable frames which are moved in the opticalaxis direction and at least two drive sources for moving the movableframes, and at least two movable frames which are moved by the otherdrive source are arranged with at least one movable frame which is movedby one drive source interposed therebetween, the assembling becomesdifficult. Further, when two drive sources are held by two differentmembers, and two members are separated from each other or joined to eachother, the assembling becomes difficult.

To overcome the above-mentioned drawbacks, the lens barrel according tothe present disclosure includes: the first drive source; the seconddrive source; the first movable frame; the second movable frame; thefirst moving mechanism driven by the first drive source; the secondmovable mechanism driven by the second drive source; the first supportmember on which the first moving mechanism is arranged and which movablysupports the first movable frame and the second movable frame in theoptical axis direction; and the intermediate member which is driven bythe second moving mechanism, wherein a drive force is transmitted to thefirst movable frame by the first moving mechanism, and a drive force istransmitted to the second movable frame by way of the intermediatemember. Further, the lens barrel of the present disclosure includes thesecond support member on which the second movable mechanism is arranged,and movably supports the intermediate member in the optical axisdirection. The cam mechanism is used as the second moving mechanism. Thefirst support member and the second support member are configured to beseparable from each other and are joinable to each other. The firstmoving frame is arranged more on a second support member side than thesecond movable frame in the optical axis direction, and at least aportion of the intermediate member is arranged outside the first movableframe or the lens group mounted on the first movable frame in the radialdirection. Further, at least one of the contact surface of theintermediate member and the contact surface of the second movable frameis set as a surface approximately orthogonal to the optical axisdirection. In the present disclosure, the first drive source is formedof the focus motor unit 610, the second drive source is formed of thezooming motor unit 910, the first movable frame is formed of the fourthgroup unit 400, the lens group mounted on the first drive frame isformed of the fourth lens group L4, the second movable frame is formedof the fifth group unit 500, the first moving mechanism is formed of thescrew feeding mechanism of the focus motor unit 610, the second movingmechanism is formed of the cam mechanism which is constituted of thedrive cam groove 1036 and the cam follower 523, the first support memberis the master flange unit 600, the second support member is a unitconstituted of the fixed frame 900, the penetration cam frame 1100, therotation restricting frame 1200, the drive frame unit 1000 and thedouble-sided cam frame 1310, and the intermediate member is formed ofthe fifth group drive arm 520.

With this constitution, assembling can be performed easily withoutdeteriorating moving accuracy of the movable frame. Further, it ispossible to provide the lens barrel which can be easily assembledwithout increasing drive sources and movable mechanisms.

(Effects and the Like)

The lens barrel according to the present disclosure includes: at leastone lens; the optical axis of the lens; the first frame (the fixed frame900) having the first restricting portion (the restricting portion 901,the restricting portion 902) and having an approximately cylindricalshape about the optical axis; the second frame (the drive frame unit1000) having the cam groove (the driving cam groove 1036) and having anapproximately cylindrical shape about the optical axis; the third frame(the fifth group lens frame 510) having the guide portion (the guideportion 511) which restricts inclination thereof with respect to thefirst contact portion (the contact portion 514) and the optical axis andhaving an approximately cylindrical shape about the optical axis; thedrive arm (the fifth group drive arm 520) having a cam follower (the camfollower 523), the second restricting portion (the radial directionrestricting portion 524, the rotational direction restricting portion525) and the second contact portion (the contact portion 526), andhaving an approximately arcuate shape constituted of a portion of acircular cylinder about the optical axis or an approximately plateshape; the guide shaft (the guide shaft 601) for guiding the guideportion (the guide portion 511) in a movable manner in the optical axisdirection; and the spring (the biasing spring 603). The firstrestricting portion (the restricting portion 901, the restrictingportion 902) engages with the second restricting portion (the radialdirection restricting portion 524, the rotational direction restrictingportion 525). The cam follower (the cam follower 523) engages with thecam groove (the driving cam groove 1036). The drive arm (the fifth groupdrive arm 520) moves approximately parallel to the optical axis due tothe relative rotation of the second frame (the drive frame unit 1000)with respect to the first frame (the fixed frame 900), the third frame(the fifth group lens frame 510) is biased by the spring (the biasingspring 603) thus bringing the first contact portion (the contact portion514) and the second contact portion (the contact portion 526) intocontact with each other, and the third frame (the fifth group lens frame510) moves in the optical axis direction in an interlocking manner withthe drive arm (the fifth group drive arm 520) with the inclination ofthe guide portion (the guide portion 511) being restricted by the guideshaft (the guide shaft 601).

With this constitution, the lens barrel of the drive arm (the fifthgroup drive arm 520) can be miniaturized (can be made thin) in theoptical axis direction.

In the lens barrel according to the present disclosure, the firstrestricting portion (the restricting portion 901, the restrictingportion 902) includes the first radial direction restricting portion(the restricting portion 901) and the first rotational directionrestricting portion (the restricting portion 902), the secondrestricting portion (the radial direction restricting portion 524, therotational direction restricting portion 525) includes the second radialdirection restricting portion (the radial direction restricting portion524) and the second rotational direction restricting portion (therotational direction restricting portion 525), the first rotationaldirection restricting portion (the restricting portion 902) and thesecond rotational direction restricting portion (the rotationaldirection restricting portion 525) engage with each other, and the firstradial direction restricting portion (the restricting portion 901) andthe second radial direction restricting portion (the radial directionrestricting portion 524) engage with each other.

With this constitution, a change in position of the drive arm (the fifthgroup drive arm 520) in the rotational direction and the radialdirection can be restricted.

In the lens barrel according to the present disclosure, the drive arm(the fifth group drive arm 520) includes the third restricting portion(the rotation restricting portion 521, the radial direction restrictingportion 522), and the lens barrel includes the fourth frame (1100)having the fourth restricting portion (the restricting portion 1110, theguide groove 1111) which engages with the third restricting portion (therotation restricting portion 521, the radial direction restrictingportion 522) and has an approximately cylindrical shape about theoptical axis.

With this constitution, by the third restricting portion (the rotationrestricting portion 521, the radial direction restricting portion 522)and the fourth restricting portion (the restricting portion 1110, theguide groove 1111) of the fourth frame (1100), the first restrictingportion (the restricting portion 901, the restricting portion 902) andthe second restricting portion (the radial direction restricting portion524, the rotational direction restricting portion 525) can restrict achange in position of the drive arm (the fifth group drive arm 520)outside a predetermined range at different positions. In thisembodiment, the second restricting portion (the radial directionrestricting portion 524, the rotational direction restricting portion525) is formed on a rear side of the drive arm (the fifth group drivearm 520) in the optical axis direction and hence, a change in positionof the drive arm (the fifth group drive arm 520) outside a predeterminedrange on a rear side in the optical axis direction can be restricted. Onthe other hand, the third restricting portion (the rotation restrictingportion 521, the radial direction restricting portion 522) is formed ona front side of the drive arm (the fifth group drive arm 520) in theoptical axis direction and hence, a change in position of the drive arm(the fifth group drive arm 520) outside a predetermined range on a frontside in the optical axis direction can be restricted.

In the lens barrel according to the present disclosure, the thirdrestricting portion (the rotation restricting portion 521, the radialdirection restricting portion 522) includes the third radial directionrestricting portion (the radial direction restricting portion 522) andthe third rotational direction restricting portion (the rotationrestricting portion 521), the fourth restricting portion (therestricting portion 1110, the guide groove 1111) includes the fourthradial direction restricting portion (the restricting portion 1110) andthe fourth rotational direction restricting portion (the guide groove1111), the third rotational direction restricting portion (the rotationrestricting portion 521) and the fourth rotational direction restrictingportion (the guide groove 1111) are engage with each other, and thethird radial direction restricting portion (the radial directionrestricting portion 522) and the fourth radial direction restrictingportion (the restricting portion 1110) engage with each other.

With this constitution, a change in position of the drive arm (the fifthgroup drive arm 520) in the rotational direction and the radialdirection can be restricted. In this embodiment, the third radialdirection restricting portion (the radial direction restricting portion522) and the third rotational direction restricting portion (therotation restricting portion 521) are formed on a front side of thedrive arm (the fifth group drive arm 520) in the optical axis directionand hence, a change in position of the drive arm (the fifth group drivearm 520) in the rotational direction and the radial direction on a frontside in the optical axis direction can be restricted. On the other hand,the second radial direction restricting portion (the radial directionrestricting portion 524) and the second rotational direction restrictingportion (the rotational direction restricting portion 525) are formed ona rear side of the drive arm (the fifth group drive arm 520) in theoptical axis direction and hence, a change in position of the drive arm(the fifth group drive arm 520) in the rotational direction and theradial direction on a rear side in the optical axis direction can berestricted.

In the lens barrel according to the present disclosure, the lens barrelincludes the fifth frame (the fourth group unit 400) movable in theoptical axis direction, and at least a portion of the drive arm (thefifth group drive arm 520) is arranged outside the fifth frame (thefourth group unit 400) or a group of lenses (the fourth lens group L4)mounted on the fifth frame (the fourth group unit 400) in a radialdirection.

With this constitution, at least a portion of the drive arm (the fifthgroup drive arm 520) can be arranged at the same position as the fifthframe (the fourth group unit 400) or the group of lenses (the fourthlens group L4) mounted on the fifth frame (the fourth group unit 400) inthe optical axis direction. Accordingly, the lens barrel can beminiaturized (can be made thin) in the optical axis direction.

In the lens barrel according to the present disclosure, the lens barrelincludes: the first motor unit (the focus motor unit 610) which drivesthe fifth frame (the fourth group unit 400) for positioning the fifthframe (the fourth group unit 400) in the optical axis direction; and thesecond motor unit (the zooming motor unit 910) which drives the secondframe (the drive frame unit 1000) in a rotatable manner.

With this constitution, the fifth frame (the fourth group unit 400) canbe driven for positioning the fifth frame (the fourth group unit 400) inthe optical axis direction by the first motor unit (the focus motor unit610), and the second frame (the drive frame unit 1000) can be driven ina rotatable manner by the second motor unit (the zooming motor unit910).

In this embodiment, although the first restricting portion isconstituted of the restricting portion 901 and the restricting portion902, and the second restricting portion is constituted of the radialdirection restricting portion 524 and the rotational directionrestricting portion 525, the constitution of the first restrictingportion and the constitution the second restricting portion are notlimited to such a constitution. The first restricting portion and thesecond restricting portion may adopt any constitution provided that thefirst restricting portion and the second restricting portion canrestrict a change in position outside a predetermined range (a change inposition in the rotational direction and the radial direction and thelike) due to the engagement of the first restricting portion and thesecond restricting portion to each other. For example, one restrictingportion out of the first restricting portion and the second restrictingportion may be constituted of a shaft-like member which extends in theoptical axis direction, and the other restricting portion may beconstituted of a cylindrical bearing member, for example, through whichthe shaft-like member is inserted and which supports the shaft-likemember in a movable manner in the optical axis direction.

[4. Others]

In some paragraphs of the embodiment, subject matters are described in amanner of “a name of subject matter (a name of concrete subject matter)”such as “a first frame (a first group unit 100)”, “a first frame (apenetration cam frame 1100)”, and “a first frame (a fixed frame 900)”,there are cases where a name of subject matter “a first frame” is usedwith respect to “a first group unit 100”, “a penetration cam frame1100”, and “a fixed frame 900”. These expressions do not mean that anyone of “a first group unit 100”, “a penetration cam frame 1100”, and “afixed frame 900” may be used as “a first frame”. Names “first frame” ineach paragraph are generalized names in each paragraph with respect to“a first group unit 100”, “a penetration cam frame 1100”, and “a fixedframe 900”. It is the same with respect to “a second frame (adouble-sided cam frame 1310)”, “a second frame (a first drive frame1020)”, and “a second frame (a drive frame unit 1000)”. Further, it isthe same with respect to other subject matters described in the sameexpressing manner.

The embodiment has been described heretofore as an example of thetechnique according to the present disclosure. For this purpose, theattached drawings and the detailed description are provided.

Accordingly, the constitutional elements described in the attacheddrawings and the detailed description may also include not only theconstitutional elements necessary for solving the problems but alsoconstitutional elements which are unnecessary for solving the problemsin order to exemplify the aforementioned techniques. Therefore, suchunnecessary constitutional elements should not be immediately determinedto be necessary, for the reason that these unnecessary constitutionalelements are described in the attached drawings and the detaileddescription.

Further, the aforementioned embodiment is merely for exemplifying thetechniques according to the present disclosure and, therefore, variouschanges, replacements, additions, omissions and the like can be madethereto within the scope of the claims and scopes equivalent thereto.

INDUSTRIAL APPLICABILITY

The present disclosure is applicable to an imaging apparatus. To be morespecific, the present disclosure is applicable to a digital stillcamera, a movie set, a mobile phone equipped with a camera function, asmartphone and the like.

What is claimed is:
 1. A lens barrel comprising: a first frame; a secondframe which is rotatably supported relative to the first frame about anoptical axis, and has a first groove; a third frame which is rotatablysupported relative to the first frame about the optical axis, and has asecond groove; a fourth frame which has a first follower which isengageable with the first groove and the second groove and is movablewith respect to the second frame and the third frame in the optical axisdirection; and a moving mechanism which moves the third frame relativeto the second frame in the optical axis direction when the third frameis rotated relative to the first frame, wherein the first follower isformed in a shape by which the first follower can continuously transitbetween the first groove and the second groove.
 2. The lens barrelaccording to claim 1, wherein the moving mechanism is constituted of acam mechanism.
 3. The lens barrel according to claim 2, wherein the cammechanism is constituted of a cam follower of the first frame and a camgroove of the third frame.
 4. The lens barrel according to claim 3,wherein the second frame has a first rotation restricting portion, andthe third frame has a second rotation restricting portion which engageswith the first rotation restricting portion.
 5. The lens barrelaccording to claim 1 further includes a drive motor where a drive gearis joined to the drive shaft, a driven gear portion which engages withthe drive gear of the drive motor and rotates the third frame about theoptical axis is formed on a rear end side of an outer circumferentialsurface of the third frame in the circumferential direction, and thedriven gear portion is formed so as to make a predetermined angle withrespect to the circumferential direction such that one end side of thedriven gear portion in the circumferential direction projects toward arear side from a rear end of the third frame.